The assassination of Nasrallah and the shaking of trust between Iran and Hezbollah

The assassination of Hezbollah leader Hassan Nasrallah last week has shaken trust between Iran and the group it created in the 1980s to oppose Israel. A large number of sources from Iran, Lebanon and the Hezbollah group itself, who have spoken to the Reuters news agency, have shown how they have launched deep investigations and interrogations and even suspicions of Israeli infiltration within them. Iran's Supreme Leader Ayatollah Khamenei no longer trusts anyone after Nasrallah's assassination, one of the sources said.

Iran's Supreme Leader Ayatollah Ali Khamenei had warned Hezbollah leader Syed Hassan Nasrallah to leave Lebanon days before he was killed in an Israeli strike and is now deeply concerned about Israeli infiltration of the top ranks of government in Tehran, three Iranian sources told Reuters.

Shortly after the explosion of Hezbollah pagers on September 17, Khamenei had sent a person to plead with Hezbollah's secretary general to leave for Iran, based on intelligence reports that Israel had operatives inside Hezbollah and was planning the assassination his, a senior Iranian official said.

The envoy, the official said, was a senior commander of the Iranian Revolutionary Guard Corps (IRGC), Brigadier General Abbas Nilforoushan, who was with Nasrallah in his bunker when he was hit by Israeli bombs and also killed.

Khamenei, who has been holed up inside Iran since Saturday, ordered a barrage of about 200 rockets fired into Israel on Tuesday, according to the Iranian official. 

The attack was revenge for the deaths of Nasrallah and Nilforoushan, the Revolutionary Guards said in a statement. It also mentioned the July assassination of Hamas leader Ismail Haniyeh in Tehran and Israel's attacks on Lebanon. Israel has not claimed responsibility for Haniyeh's death. 
Israel on Tuesday launched what it described as a "limited" ground incursion against Hezbollah in southern Lebanon.

Nasrallah's killing followed two weeks of precision Israeli strikes that have destroyed weapons facilities, eliminated half of Hezbollah's ruling council and decimated the military's high command.

Iran's fears for Khamenei's safety and a loss of confidence, both within Hezbollah and in Iran's leadership, emerged in conversations with 10 sources for this story, who described a situation that could complicate the effective operation of anti-Israeli armed groups, of the Axis of Resistance of Iran alliance.

Founded with Iranian support in the 1980s, Hezbollah has long been the most feared member of the Alliance.

The rift is also making it difficult for Hezbollah to choose a new leader, fearing that continued infiltration will jeopardize the successor, four Lebanese sources said.

"Essentially, Iran lost the biggest investment it had for decades," said Magnus Ranstorp, a Hezbollah expert at the Swedish Defense University, who added that the deep damage inflicted on Hezbollah reduces Iran's capacity to hit Israel's borders.
"It shook Iran to its core. This shows how Iran is also deeply infiltrated: they not only killed Nasrallah, but also killed Nilforoushan," he said.

Nilforoushan was a trusted military adviser to Khamenei.

Hezbollah's lost military capacity and leadership could push Iran toward the kind of attacks against Israeli embassies and personnel abroad that it more frequently engaged in before the rise of its proxy forces, according to Ranstorp.

Iran makes arrests

Nasrallah's death has prompted Iranian authorities to thoroughly investigate possible infiltration within Iran's ranks, from the powerful Revolutionary Guard to senior security officials, a second senior Iranian official told Reuters. They are particularly focused on those who travel abroad or have relatives living outside Iran, the first official said.

Tehran became suspicious of some Guardsmen who had traveled to Lebanon, he said. Concerns arose when one of these individuals began asking about Nasrallah's whereabouts, specifically asking how long he would be staying in specific locations, the official added.

He was arrested along with several others, the first official said, after the alarm was raised in Iranian intelligence circles. The suspect's family had moved outside Iran, the official said, without identifying the suspect or his relatives.

The second official said the killing has fueled mistrust between official Tehran and Hezbollah and within Hezbollah itself.

"The trust that held everything together has disappeared", said the official.

The supreme leader "doesn't trust anyone anymore", said a third source who is close to Iran's institutions.

"Alarm bells" were already ringing within Tehran and Hezbollah about possible Mossad (Israeli intelligence agency) infiltrations after the July killing of Hezbollah commander Fuad Shukr in an Israeli airstrike on a secret location in Beirut while was meeting an IRGC commander, two Hezbollah sources and a Lebanese security official told Reuters. This assassination took place hours after the assassination of Hamas leader Haniyeh in Tehran.
Unlike Haniyeh's death, Israel publicly claimed responsibility for the killing of Shukr, a low-profile figure whom Nasrallah nevertheless described, at his funeral, as a central figure in Hezbollah's history who had built the most important capabilities of the group.

Shukr was key to developing Hezbollah's most advanced weaponry, including precision-guided missiles, and was responsible for the Shiite group's operations against Israel over the past year, the Israeli military said.

Iranian fears of Israeli infiltration of its top ranks go back many years. In 2021, former Iranian President Mahmoud Ahmadinejad said the head of an Iranian intelligence unit that was supposed to target Mossad agents was himself an agent of the Israeli spy agency, telling CNN Turkey that Israel had obtained documents sensitive information on Iran's nuclear program, a reference to a 2018 raid in which Israel obtained a large amount of top-secret documents related to the program.

Also in 2021, Israel's outgoing spy chief, Yossi Cohen, gave details about the attack, telling the BBC that 20 non-Israeli Mossad agents were involved in stealing the archive from a warehouse.

Warning after pagers

Khamenei's invitation to Nasrallah to relocate to Iran came after thousands of pagers and radios used by Hezbollah were blown up in deadly attacks on September 17 and 18 in Lebanon and Syria, the first official said. The attacks have been attributed to Israel, although the state has not officially claimed responsibility.

Nasrallah, however, felt safe and fully trusted his inner circle, the official said, despite Tehran's serious concerns about potential infiltrators within Hezbollah's ranks.

Khamenei tried a second time, relaying another message through Nilforoushan Nasrallah last week, begging him to leave Lebanon and move to Iran as a safer place. But Nasrallah insisted on staying in Lebanon, the official added.

Several high-level meetings were held in Tehran after the pager blasts to discuss the security of Hezbollah and Nasrallah, the official said, but declined to say who attended those meetings.

Simultaneously, in Lebanon, Hezbollah began conducting a major investigation to purge Israeli spies among them, interrogating hundreds of members after the pager blasts, three sources in Lebanon told Reuters.

Sheikh Nabil Kaouk, a senior Hezbollah official, was leading the investigation, a Hezbollah source said. The investigation was progressing rapidly, the source said, before an Israeli strike killed him a day after Nasrallah's assassination. Another attack earlier last week targeted other senior Hezbollah commanders, some of whom were involved in the investigation.
Kaouk had called to question Hezbollah officials involved in logistics and others "who participated, brokered and received offers for pagers and radio connections," the source said.

A "deeper and more comprehensive investigation" as well as a "purge" was much needed after the killing of Nasrallah and other commanders, according to the source.

Ali al-Amin, editor-in-chief of Janoubia, a Shiite community-based news site and Hezbollah, said reports indicated that Hezbollah had detained hundreds of people for questioning following the pager saga.

Hezbollah is reeling from Nasrallah's assassination deep in its headquarters bunker, shocked at how successfully Israel penetrated the group, seven sources told Reuters. 
Mohanad Hage Ali, deputy director of the Carnegie Center for the East in Beirut focusing on Iran and Hezbollah, described the offensive as "the biggest intelligence infiltration by Israel" since Hezbollah was founded with Iranian support in the 1980s.

The current Israeli escalation follows almost a year of cross-border fighting after Hezbollah launched rocket attacks in support of its ally Hamas. The Palestinian group killed 1.200 people and kidnapped 250 others in an attack on Israel on October 7, 2023, according to Israeli records.

Israel's retaliation in Gaza has killed more than 41.000 Palestinians, according to the Gaza Ministry of Health.

Loss of faith

The Israeli offensive and fears of more attacks on Hezbollah have also prevented the Iran-backed group from organizing a nationwide funeral on a scale that reflects Nasrallah's religious and leadership status, according to four sources familiar with the debate within Hezbollah.

"No one can authorize a funeral under these circumstances," a Hezbollah source said, referring to the situation in which officials and religious leaders cannot appear to properly honor the late leader.

Several commanders killed last week were discreetly buried on Monday, with plans for a proper religious ceremony when the conflict ends.

Hezbollah is considering securing a religious decree to temporarily bury Nasrallah and hold an official funeral when the situation allows, the four Lebanese sources said.

Hezbollah has refrained from formally naming a successor to Nasrallah, perhaps to avoid making his replacement a target for an Israeli assassination, they said.

"The appointment of a new secretary-general could be dangerous if Israel kills him immediately afterwards. The group cannot risk more chaos by appointing someone only to see him killed," said Amin.