On October 1, the Israel Defense Forces (IDF) announced the killing of Mohammad Jaafar Qasir, a high-value Hezbollah operative who commanded the group’s Unit 4400—the body responsible for transporting weapons from Iran and its proxies to Hezbollah in Lebanon. The Israeli strike focused attention on this shadowy unit whose activities are vital to Hezbollah’s battle-readiness.

What is Unit 4400? A history of the organization and its activities

Unit 4400 is also known as Unit 108 within Hezbollah or, alternatively, is believed to be a subunit of Unit 108 that operates in Syria. After the assassination of Hezbollah Chief of Staff Imad Mughniyeh in Damascus in 2008, Hezbollah took it upon itself to create and secure weapons transfer routes from Iran to the group within Lebanon. This effort led Hezbollah to establish a network of offices and units within Syria to facilitate this process. In the three years prior to the Syrian Civil War and during the first years of that conflict, three units within Hezbollah assumed this task: Unit 100, Unit 108/4400, and Unit 112. Unit 108/4400 was the most significant and influential among them.

Unit 108/4400 was headquartered in Damascus, Syria, and assumed the primary task of transferring weapons between countries where the Iran-led Axis of Resistance was influential (namely, Iran, Iraq, and Syria) to the Lebanese border. Unit 112 would then receive these weapons and distribute them to Hezbollah’s weapons warehouses inside Lebanon, while Unit 100 was tasked with transporting Hezbollah’s fighters and leaders, plus Iranian advisors, between Lebanon, Syria, and Iran.

Hezbollah’s involvement in the Syrian Civil War led to the expansion of Unit 108/4400’s duties. The unit began to store weapons in warehouses inside Syria and developed an extensive presence throughout that country, particularly in Aleppo.

Israel began publicly identifying the unit’s activities in 2018, referring to it as “Unit 4400,” though the Israelis had been previously tracking its activities for years. Unit 4400 began specializing in acquiring and smuggling “sensitive weaponry,” including sophisticated weapons, precision-guided missiles, modern drones, and loitering munitions, to Hezbollah’s weapons depots in Lebanon. Unit 4400 operatives would travel to, among other places, Latakia Port in Syria and the Bukamal region on the Syria-Iraq border to collect weapons shipped by sea or land from Iran and destined for Hezbollah. Reports indicate that once these smuggled arms reach Lebanon, Unit 4400 members often stored them temporarily before distributing them to various Hezbollah divisions.

Unit 4400 had an additional task: transporting and transferring funds, whether via financial support provided by Iran, from trading oil in Syria, or resulting from Hezbollah’s private investments. Based on IDF targeting, it would seem that Unit 4400 also smuggled and stored fuel in Lebanon.

Israel launched a campaign of airstrikes against Unit 4400 and its assets during the conflict with Hezbollah that began in October 2023. Here are some highlights of this campaign, which peaked in September 2024:

• February 10, 2024: Israel struck Dimas Airport in Syria, most likely targeting an assembly point for drone parts obtained from Iran and Syria before being transferred by Unit 4400 into Lebanon. Israel first reportedly struck the site in October of 2022.
• June 10, 2024: Israeli jets struck a military compound belonging to Unit 4400 “deep inside Lebanon” in the vicinity of Baalbek.
• September 8, 2024: Israel Air Force (IAF) Shaldag Unit commandos conducted a special forces raid on Masyaf in northwestern Syria while covered by Israeli airstrikes. The raid led to the destruction of a PGM and drone factory, according to some sources that were under Unit 4400’s supervision.
• July 9, 2024: An Israeli airstrike targeted a car carrying Yasser Nimr Qranbish on the Beirut-Damascus International Highway, killing him.
• September 30, 2024: Israel hit Dimas Airport again.  
• In October, four Israeli airstrikes on the Mezzeh in Damascus killed several Unit 4400 commanders.
• October 3, 2024: An Israeli airstrike targeted a warehouse near the Russian-controlled Hmeimim Airbase. The facility, reportedly previously used to store food, had been converted to a Hezbollah missile storage site. The warehouse was reportedly controlled by Unit 4400. The strike occurred hours after the arrival of an Iranian Qeshm Air flight, an airline owned by the sanctioned Mahan Air, and sanctioned itself for links to the Islamic Revolutionary Guard Corps-Quds Force (IRGC-QF) and ferrying weapons on its behalf.
• October 4, 2024: Israeli F-35 jets struck and destroyed a 3.5 km tunnel that crossed from Syria into Lebanon that Unit 4400 had been using to smuggle weapons from Iran. The tunnel appears to have been near the Al-Masnaa Border Crossing, the central crossing point between Lebanon and Syria.
• October 6, 2024: An Israeli airstrike targeted weapons warehouses, allegedly storing missiles, in Homs and Hama. The warehouses were reportedly supervised by Unit 4400.
• October 8, 2024: An Israeli airstrike hit Building 14 in the al-Sheikh Saad area of the Mezzeh neighborhood of Damascus—where Hezbollah and the IRGC own several budlings, especially in the neighborhood’s more affluent areas. The strike killed “Hajj Samer,” a commander in Unit 4400—most likely Hassan Jaafar Qasir, Nasrallah’s son-in-law named after his older deceased brother Hassan—and another unidentified Hezbollah member.
• October 21, 2024: Israel killed Qasir’s successor in the Mezzeh neighborhood of Damascus
• October 25, 2024: Israeli jets struck Hezbollah infrastructure on the Syrian-controlled Jusiyah Border Crossing in the northern Beqaa Valley, which Unit 4400 had been using to smuggle weapons into Lebanon. This, according to the IDF, was one of many strikes it conducted that month against Syria-Lebanon border crossings being used by Unit 4400.
• October 30, 2024: Israeli jets struck silos belonging to Unit 4400 in Baalbek, destroying fuel used for various Hezbollah vehicles. The IDF said that Iran supplied the fuel as part of its support for the group.
• October 31, 2024: Israeli jets struck Hezbollah weapons depots being used by the Radwan Force in al-Qusayr, Syria. These depots were under Unit 4400’s supervision, which the IDF’s statement claimed had “recently expanded its activities in Syria to al-Qusayr, near the Syria-Lebanon border.” Two or three unidentified individuals were reportedly killed in the strike.
• November 1, 2024: Israel’s elite Shayetet 13 naval commandos landed on the coast of Batroun and seized a Hezbollah operative, taking him back to Israeli territory. The alleged operative was later identified as Baalbek native Imad Amhaz, who credible sources claimed was engaged in maritime smuggling on behalf of Unit 4400.
• November 5, 2024: Israel claimed a strike on Unit 4400’s weapons depots in the area of al-Qusayr, Syria.

Unit 4400’s leaders and their contributions to the unit’s development

Israel’s intensified pursuit of Unit 4400 culminated in the assassination of Qasir on October 1. Also known as Hajj Fadi/Sheikh Salah, Qasir was born on February 12, 1967, in Dayr Qanun al-Nahr in south Lebanon. He is the younger brother of Ahmad Jaafar Qasir, a 19-year-old member of Hezbollah at the time of his death who drove an explosives-laden car into the IDF’s military headquarters in the city of Tyre in southern Lebanon on November 11, 1982. The attack killed 71 Israeli soldiers, officers, and Shin Bet agents alongside dozens of Lebanese and Palestinian prisoners. The operation’s date became Hezbollah’s annual “Martyr’s Day” commemoration. A year later, Ahmad and Mohammad’s other brother, Hassan, reportedly struck the Tyre HQ again with an explosives-laden truck on November 4, 1983, killing 28 Israelis and 32 Lebanese.

Mohammad Qasir appears to have followed in his brothers’ footsteps into Hezbollah, though it is unknown when he joined the organization. After the assassination of Mughniyeh, Qasir began to rise to prominence. He is believed to have assumed command of Unit 4400 before 2010 and held the role until his assassination, overseeing countless operations transferring strategic weapons to Hezbollah.

In time, Qasir would assume the role of a critical financial conduit between the IRGC’s Quds Force and its Lebanese franchise. On April 17, 2018, Qasir and a Syrian associate received over $63 million to benefit Hezbollah, a figure he confirmed in a letter to a senior official at the Central Bank of Iran. In a testament to his organizational significance, Qasir also became a close confidante of then-IRGC-QF Commander Qassem Soleimani and Hezbollah Secretary-General Hassan Nasrallah. On February 25, 2019, Qasir even accompanied Soleimani as a notetaker for meetings between Syrian President Bashar al-Assad, his Iranian counterpart Hassan Rouhani, and Supreme Leader Ayatollah Ali Khamenei.

Alongside arms smuggling, Qasir and Unit 4400 have been rumored, per some unsubstantiated reports, to be involved in drug trafficking operations. If these rumors are true, it seems that Qasir used Unit 4400’s established supply lines to smuggle narcotics across Syria and Lebanon while collaborating closely with the IRGC and Syria’s 4th Armored Division commanded by Bashar al-Assad’s brother, Maher.

Qasir’s activities, including acting as one of Hezbollah’s primary financial architects and using smuggling networks to fund the organization’s operations and bolster its regional influence, led the United States Treasury Department’s Office of Foreign Assets Control to designate him as a Specially Designated Global Terrorist on May 15, 2018. Two years later, the State Department’s Rewards for Justice Program offered  $10 million for information leading to the disruption of Qasir’s activities.

After the assassination of Mustafa Badreddine, Mughniyeh’s successor, in 2016, Qasir’s prominence again rose. His Unit 4400 would further tighten ties with the IRGC, and he would become involved in smuggling Iranian oil, generating substantial revenues for Hezbollah. According to IDF Spokesman Daniel Hagari, Qasir was also responsible for “financial transfers to Hezbollah” derived from sales of Iranian oil and other sources, allegedly worth “hundreds of millions of dollars a year.”

After Qasir’s assassination, his unidentified successor took his place as the head of Unit 4400. However, he did not last long in that role. On October 21, Qasir’s successor was killed alongside an unidentified companion in the Mezzeh neighborhood of Damascus, Syria, near a memorial service being held for Yahya Sinwar. According to an IDF spokesperson, the commander was responsible for managing financial transactions within the organization and had command over Unit 4400. Although the IDF did not release the commander’s name, Hezbollah-affiliated social media accounts eulogized Ali Hassan Gharib, also known as Ayman Abu Hassan, claiming he had been killed in Syria on the same day.

Other Unit 4400 members and affiliates

• Yasser Nemr Qranbish, a former bodyguard for Hassan Nasrallah, was killed in an Israeli airstrike on his vehicle that was traveling along the Beirut-Damascus International Highway. Qranbish reportedly assumed a command role within Unit 4400 after his bodyguard post.
• Ali Abdul Nour Shaalan holds a significant role in managing the financial affairs of Unit 4400. Shaalan was accused by Hezbollah of embezzling $5 million in 2022, which led to his detention by a protection unit run by a member of the Awada family. However, Qasir intervened, using his influence and connections with Iranian allies to secure Shaalan’s release.
• Alongside Shaalan, Mohammad Al Bazzal, also known as “Haj Mu’in,” was considered a personal aide of Qasir and photographed next to him near Shebaa farms in 2022. Al-Bazzal is married to Qasir’s daughter Fatima and served as the head of financial affairs for the unit. He is also sanctioned by the United States.
• Reports have indicated that Imad Amhaz, who was captured by Israel’s Shayetet 13 in Batroun on November 1, is likely connected to maritime smuggling for Hezbollah’s Unit 4400.
• Mohammad Baraa Qaterji, also known as “Hajj Baraa,” was responsible for the smuggling of Syrian oil in coordination with Unit 4400. Hajj Baraa’s company, Qaterji International Group, is connected to the IRGC-QF and has transported Iranian oil to Syria on multiple occasions. A report from 2019 suggested that Qaterji and Unit 4400 had financial disputes because of Qaterji’s failure to settle its debts to Iran due to a cash shortage at the Syrian Central Bank. Qaterji was killed in an Israeli airstrike on July 15.

Unit 4400 coordinates closely with IRGC-QF’s Unit 190 and Unit 700 in smuggling weapons into Lebanon. Some of the individuals who are behind the transfers of weapons from Iran to Hezbollah include:

• Ali Mohammad Taghvi is responsible for Unit 4400’s warehouse in Tehran.
• Brigadier General Ali Naji is with Unit 700 based in Tehran.
• Colonel Sayyed Jalal Ahmadi is thecommander of the 15^th Khordad Missile Group in the IRGC’s Ground Forces.
• Saeed Dirani coordinates weapon transfers and supplies.
• Abul Fazl Salmani Zadegan is with Unit 700 based in Syria.

Israel’s purpose for targeting Unit 4400 and the impact of these attacks

Between October 8, 2023—when Hezbollah began attacking Israel—and September 16, 2024, Israel and Hezbollah were locked in a state of mutual attrition. However, starting with its dual telecommunications device attacks on September 17 and September 18, Israel began rapidly executing a strategy to cripple Hezbollah’s ability to use its massive arsenal—before turning to destroy the arsenal itself.

The Israelis aimed at disrupting the group’s communications and assassinating its senior military and political leadership. Israel’s focused attacks on Unit 4400 that escalated around the same time were likely a continuation of this strategy, meant to suffocate Hezbollah by crippling its ability to acquire more arms and funds—thus undermining the group’s capability to continue fighting.  

Hezbollah, predictably, denies that this strategy has significantly impacted its operations or that Israel has had much success in degrading the group’s assets and arsenal. However, Hezbollah can’t be expected to admit such weaknesses. Unless the group is holding back unleashing its full strength as part of a larger plan, the Israeli strategy seems to be working, having prevented the apocalyptic scenarios expected to occur during the next Israel-Hezbollah war. Degrading Unit 4400’s personnel, assets, and resulting capabilities certainly contributes to this outcome. Hezbollah stumbled into a long conflict with Israel that it was not anticipating and which does not seem to be ending soon. If the group’s access to weapons and material is being strangled by Israeli military action against Unit 4400, the situation could force the group to ration what remains of its arsenal, which would explain its reduced rate of daily fire on Israel.

However, it is too soon to speak of a long-term impact on Hezbollah of Israel’s degradation of Unit 400 beyond the current conflict. Hezbollah is a 42-year-old organization with a complex hierarchy and chain of succession. The group has, therefore, likely been able to fill all the vacancies left by the spate of Israeli assassinations, albeit, admittedly, with seemingly inferior or less-experienced replacements. However, if Hezbollah remains standing at the end of the current conflict, those individuals will continue to acquire the sophistication that comes with time and may learn the lessons of the current war with Israel. The group’s newer leaders could use this knowledge to reestablish Unit 4400’s supply lines—with which Hezbollah could begin rebuilding its arsenal.

David Daoud is senior fellow at the Foundation for Defense of Democracies, where he focuses on Israel, Hezbollah, and Lebanon affairs. Ahmad Sharawi is a research analyst at the Foundation for Defense of Democracies focused on Iranian intervention in Arab affairs and the Levant.

Tags: Axis of Resistance, hezbollah, IDF, Iran, IRGC-Qods Force, Israel Hezbollah, lebanon, Syria, Unit 4400