ISW Blog: Iran Update, December 17, 2023

Ashka Jhaveri, Andie Parry, Kathryn Tyson, and Nicholas Carl

Information Cutoff: 2:00 pm EST

The Iran Update provides insights into Iranian and Iranian-sponsored activities abroad that undermine regional stability and threaten US forces and interests. It also covers events and trends that affect the stability and decision-making of the Iranian regime. The Critical Threats Project (CTP) at the American Enterprise Institute and the Institute for the Study of War (ISW) provides these updates regularly based on regional events. For more on developments in Iran and the region, see our interactive map of Iran and the Middle East.

Note: CTP and ISW have refocused the update to cover the Israel-Hamas war. The new sections address developments in the Gaza Strip, the West Bank, Lebanon, and Syria, as well as noteworthy activity from Iran’s Axis of Resistance. We do not report in detail on war crimes because these activities are well-covered in Western media and do not directly affect the military operations we are assessing and forecasting. We utterly condemn violations of the laws of armed conflict and the Geneva Conventions and crimes against humanity even though we do not describe them in these reports.

Click here to see CTP and ISW’s interactive map of Israeli ground operations. This map is updated daily alongside the static maps present in this report.

Key Takeaways:

Israeli forces uncovered an advanced and extensive Hamas tunnel system in the northern Gaza Strip. Israeli officials reported that Mohammad Sinwar—the brother of Hamas leader in the Gaza Strip Yahya Sinwar—headed the tunnel building project.
Israeli forces continued clearing operations in Shujaiya and Jabalia in the northern Gaza Strip. The al Qassem Brigades have not claimed an attack on Israeli forces in Shujaiya since December 14.
Palestinian militias continued attacking Israeli forces near Juhor ad Dik. CTP-ISW previously assessed that Palestinian militias may be using relative safe haven in the central Gaza Strip to enable attacks on Israeli forces around Juhor ad Dik.
The IDF reported that it raided the outpost of Hamas’ Deir al Balah Battalion.
An Israeli defense correspondent reported that Hamas is transferring forces from the rest of the Gaza Strip to support its Khan Younis Brigade.
Israeli forces advanced to the central square in Bani Suheila as Palestinian militias attempted to resist Israeli advances north and east of Khan Younis.
Telecommunications services are returning to parts of the Gaza Strip after a multi-day communications blackout.
Palestinian militias conducted six indirect fire attacks from the Gaza Strip into southern Israel.
Israeli forces clashed with Palestinian fighters for several hours in Tulkarm area. Palestinian fighters separately clashed with Israeli forces around Hebron.
Iranian-backed fighters, including Lebanese Hezbollah, conducted 11 attacks from southern Lebanon into northern Israel.
The Houthi anti-shipping attack campaign continues to achieve one of its desired effects of disrupting maritime traffic headed to Israel.

Gaza Strip

Axis of Resistance campaign objectives:

Erode the will of the Israeli political establishment and public to launch and sustain a major ground operation into the Gaza Strip
Degrade IDF material and morale around the Gaza Strip.

Israeli forces uncovered an advanced and extensive Hamas tunnel system in the northern Gaza Strip. The Israel Defense Forces (IDF) reported on December 17 that its forces had uncovered four kilometers of the tunnel near the Erez crossing in recent weeks.[1] The tunnel is wide enough for vehicles to pass through it, reinforced with concrete, and connected to electricity and communications infrastructure.[2] Israel said one section of the tunnel is the largest that it has discovered in the Gaza Strip and 400 meters from Israeli territory.[3] The IDF stated that it was not familiar with the tunnel route nor its enormous scope prior to the war.[4] The Wall Street Journal published a map of the tunnel system that Hamas has created below the Gaza Strip based on data from 2014, which includes a singular tunnel running south of the Erez checkpoint.[5] The IDF published a map on December 17 of the entire tunnel network that it has uncovered, which shows a notable expansion of the tunnels’ coverage and complexity compared to the 2014 data.[6]

Israeli officials reported that Mohammad Sinwar—the brother of Hamas leader in the Gaza Strip Yahya Sinwar—headed the tunnel building project.[7] Mohammad Sinwar is Hamas’ head of logistics and manpower.[8] The IDF published a video of Mohammad Sinwar driving a car through what they said is the tunnel.[9] Another video of the tunnel shows Hamas fighters using a large tunnel drill that allowed them to develop and expand the tunnel.[10] The IDF found inside the tunnel system unspecified digging machines, which Israel had not previously observed Hamas use to construct tunnels.[11] Israel estimates that Hamas has spent millions of dollars its tunnel infrastructure throughout the Gaza Strip.[12] IDF spokesperson Rear Admiral Daniel Hagari told reporters that Hamas has diverted building materials, especially concrete, away from civilian infrastructure to build its tunnels.[13]

The al Qassem Brigades—the militant wing of Hamas—conducted a complex attack targeting the IDF at the Erez crossing on October 29.[14] The fighters infiltrated Israeli territory via a tunnel west of the checkpoint, presumably the same one Israel has uncovered. Hamas maintains approximately 500 kilometers of tunnel underneath the Gaza Strip and has consistently used it to maneuver and launch attacks on Israeli forces.[15] The tunnels also conceal operations rooms, weapons stockpiles, and rocket firing positions.[16] Israeli officials have emphasized their intention to eliminate Hamas’ tunnel network.[17]

Israeli forces continued clearing operations in Shujaiya and Jabalia in the northern Gaza Strip on December 17. Israeli forces raided an apartment building in Shujaiya and found weapons, improvised explosive devices (IEDs), grenades, and a tunnel shaft.[18] The IDF conducted an airstrike to destroy the tunnel shaft in addition to an arms depot in the house of a Hamas operative.[19] The al Quds Brigades—the militant wing of Palestinian Islamic Jihad (PIJ)—claimed that its fighters clashed with seven Israeli infantrymen and fired at them with small arms and anti-personnel munitions in Shujaiya.[20]

The al Qassem Brigades have not claimed an attack on Israeli forces in Shujaiya since December 14. CTP-ISW previously assessed that Israeli clearing operations may be disrupting Palestinian militia fighters’ ability to frequently communicate with each other.[21] Hamas’ Shujaiya Battalion is also facing active and intense IDF pressure as Israel takes out its infrastructure and command structure.[22] Israeli forces destroyed the headquarters of Hamas’ Shujaiya Battalion on December 15.[23]

Israeli forces located a tunnel shaft in a child’s room during clearing operations in Jabalia.[24] The al Quds Brigades claimed that its fighters targeted four Israeli vehicles with tandem-charge rocket-propelled grenades (RPG) and anti-armor grenades in the vicinity of Jabalia.[25] The al Aqsa Martyrs’ Brigades—the self-proclaimed militant wing of Fatah—claimed that its fighters fired RPGs at Israeli forces in Jabalia.[26]

Palestinian militias continued attacking Israeli forces near Juhor ad Dik on December 17. The al Quds Brigades claimed to mortar a concentration of Israeli forces in Juhor ad Dik on December 17.[27] The al Quds Brigades and al Qassem Brigades also claimed to conduct a combined attack targeting an Israeli Merkava tank with an unspecified explosive device in al Mughraqa, west of Juhor ad Dik.[28] The al Quds Brigades and the al Qassem Brigades have claimed several combined attacks throughout the Israel-Hamas War.[29] CTP-ISW previously assessed that Palestinian militias may be using relative safe haven in the central Gaza Strip to enable attacks on Israeli forces around Juhor ad Dik.[30] The tactical coordination on the ground and coordination at the senior level between these militias is consistent with the reality that the IDF is facing a coalition of several Palestinian militias in the Gaza Strip.

The IDF reported on December 17 that it raided the outpost of Hamas’ Deir al Balah Battalion. The IDF confiscated military training manuals and intelligence materials during the raid.[31] CTP-ISW previously reported that Israeli forces are attempting to dismantle Hamas in Deir al Balah.[32] Israeli ground and naval forces have destroyed Hamas militant infrastructure, including observation posts and weapons storage facilities, in the central Gaza Strip.[33] The Deir al Balah Battalion, which is part of Hamas’ Central Brigade, released a training video prior to beginning of the war showing its militia fighters practicing close-quarters combat in urban environments.[34]

An Israeli defense correspondent reported that Hamas is transferring forces from the rest of the Gaza Strip to support its Khan Younis Brigade.[35] Palestinian militia fighters whom Israeli forces detained in the Gaza Strip told the IDF during questioning about the reinforcements.[36] The al Qassem Brigades maintain five geographic brigades in the Gaza Strip.[37] The Israeli Army Radio journalist covering the story noted that the IDF assesses that it will take several months to defeat the Khan Younis Brigade.[38] Israel has identified Khan Younis and Rafah as Hamas strongholds given the presence of Hamas leadership and military infrastructure there.[39]

Israeli forces advanced to the central square in Bani Suheila on December 17 as Palestinian militias attempted to resist Israeli advances north and east of Khan Younis. The IDF 7th Brigade Combat Team reached the square, suggesting that the IDF advances from the north and east have linked up east of Khan Younis.[40] Israeli forces have found about 30 tunnel shafts, attacked Palestinian militia positions and observation posts, confiscated weapons, and obtained intelligence materials in the Khan Younis area over the past week.[41] The al Quds Brigades fired mortars, small arms, and anti-armor munitions at Israeli infantrymen and vehicles advancing north and east of Khan Younis.[42] The al Qassem Brigades claimed that its fighters mortared Israeli forces east of Khan Younis.[43]

The National Resistance Brigades—the militant wing of Democratic Front for the Liberation of Palestine (DFLP)—claimed that its fighters mortared Israeli military vehicles east of Rafah.[44] Detained fighters from the Gaza Strip said during questioning that Israeli forces were not yet operating in Rafah.[45]

Telecommunications services are returning to parts of the Gaza Strip after a multi-day communications blackout.[46] The Palestinian Red Crescent Society (PRSC) and NetBlocks reported that the Gaza Strip was experiencing the longest telecoms blackout since the beginning of the war.[47] Palestinian telecommunications company Jawwal reported on December 17 that its teams had repaired a damaged site to restore services in the northern Gaza Strip.[48] NetBlocks reported on December 17 that internet connectivity is being restored in parts of the Gaza Strip, noting that service remains significantly below pre-war levels.[49]

UN aid convoys began entering the Gaza Strip via the Kerem Shalom crossing on December 17. Israel said that UN aid trucks will undergo security checks at the crossing and be directly transferred into the Gaza Strip via the crossing.[50] Israel said that the opening will increase the daily volume of humanitarian aid entering the Gaza Strip.[51] The Kerem Shalom crossing was previously only an inspection site for humanitarian aid trucks.[52]

Hamas continued to message that it will not enter hostage negotiations until Israel stops its ground operation in the Gaza Strip. Hamas’ political wing posted on its Telegram on December 16 affirming its position not to resume negotiations with Israel until the end of fighting in the strip.[53] Hamas Political Bureau member and representative of Gaza city Khalil al Hayya gave an interview to al Jazeera on December 17 similarly messaging that that Hamas would be ready for a comprehensive hostage deal once Israeli clearing operations conclude.[54]

Unspecified diplomatic sources told CNN that Mossad director David Barnea met with Qatari Prime Minister Mohammed bin Abdulrahman al Thani to discuss resuming hostage negotiations.[55] The sources noted that the meeting was “positive” without expanding further.[56] Israeli Prime Minister Benjamin Netanyahu’s office told CNN on December 15 that Israel believes there are 132 hostages still in the Gaza Strip, 112 of whom are thought to be alive and 20 of whom are thought to be dead.[57]

Palestinian militias conducted six indirect fire attacks from the Gaza Strip into southern Israel on December 17. The al Qassem Brigades and al Quds Brigades each conducted two rocket attacks into southern Israel.[58] The Mujahideen Brigades—the militant wing of the Palestinian Mujahideen Movement—claimed to fire rockets at an Israeli military position in southern Israel.[59] The militia has cooperated with the al Quds Brigades prior to the Israel-Hamas war.[60] Palestinian media reported an additional rocket attack into southern Israel.[61]

Recorded reports of rocket attacks; CTP-ISW cannot independently verify impact.

West Bank

Axis of Resistance campaign objectives:

Draw IDF assets and resources toward the West Bank and fix them there

Israeli forces clashed with Palestinian fighters for several hours in Tulkarm area on December 17.[62] Palestinian fighters detonated IEDs and fired small arms at Israeli forces within the Noor Shams refugee camp in Tulkarm.[63] The al Aqsa Martyrs’ Brigades—the self-proclaimed militant wing of Fatah—claimed ambushes and IED attacks targeting Israeli forces.[64] The militia’s Tulkarm Branch called on all al Aqsa Martyrs’ Brigades branches to ”strike terror in the hearts” of Israelis by attacking Israeli forces and positions.[65] The group also alluded to a ”surprise” in the next few days. The IDF Air Force conducted drone strikes in Tulkarm and killed at least four militants during the operation.[66] Israeli forces also uncovered ready-to-use IEDs.[67] Palestinian fighters separately clashed with Israeli forces around Hebron.[68]

Palestinians gathered at Arab American University in Jenin to demonstrate in support of the Gaza Strip on December 17.[69] Several demonstrators wore Hamas regalia. Palestinian civil society groups called for additional demonstrations and strikes in the West Bank on December 18.[70] A global strike in support of Palestine is planned for December 18 as well.[71]

This map is not an exhaustive depiction of clashes and demonstrations in the West Bank.

Southern Lebanon and Golan Heights

Axis of Resistance campaign objectives:

Draw IDF assets and resources toward northern Israel and fix them there
Set conditions for successive campaigns into northern Israel

Iranian-backed fighters, including Lebanese Hezbollah (LH), conducted 11 attacks from southern Lebanon into northern Israel on December 17.[72] LH launched six rockets targeting Israeli forces near Honin.[73] LH separately fired anti-tank rockets targeting Israeli military assets and infrastructure in the Dovev area.[74] The IDF said that an Israeli tank attacked the source of the fire.[75] The IDF Air Force also said that it struck LH cells and military infrastructure in Lebanon on December 17.[76]

Iran and Axis of Resistance

Axis of Resistance campaign objectives:

Demonstrate the capability and willingness of Iran and the Axis of Resistance to escalate against the United States and Israel on multiple fronts
Set conditions to fight a regional war on multiple fronts

The Houthi anti-shipping attack campaign continues to achieve one of its desired effects of disrupting maritime traffic headed to Israel. Hong Kong-based shipping company Orient Overseas Container Line (OOCL) announced on December 17 that it would immediately stop shipping goods to and from Israel.[77] The company cited “operational issues” for the policy.[78] OOCL is the first global shipping company that CTP-ISW has observed to specifically halt operations to Israel since the Houthis began their campaign against international shipping around the Bab al Mandeb in November.[79] Global shipping giants, such as Mediterranean Shipping Company, CMA CGM, Maersk, and Hapag-Lloyd, previously announced that they would pause operations around the Red Sea but did not specify how it would affect their services to Israel.[80] Houthi spokesperson Mohammed Abdulsalam commended OOCL’s decision to stop sending ships to Israeli ports and falsely asserted that the Houthis are only attacking ships linked to Israel on December 17.[81] Several of the ships that the Houthis have attacked in recent days were en route to destinations outside of Israel, such as Saudi Arabia.