By Ronen Bergman, Mark Mazzetti and Farnaz Fassihi

Ismail Haniyeh, a top leader of Hamas, was assassinated Wednesday (July 31) by an explosive device covertly smuggled into the Tehran guesthouse where he was staying, according to seven Middle Eastern officials, including two Iranians, and a US official.

The bomb had been hidden approximately two months ago in the guesthouse, according to five of the Middle Eastern officials. The guesthouse is run and protected by Iran’s Revolutionary Guard and is part of a large compound, known as Neshat, in an upscale neighbourhood of northern Tehran.

Haniyeh was in Iran’s capital for the presidential inauguration. The bomb was detonated remotely, the five officials said, once it was confirmed that he was inside his room at the guesthouse. The blast also killed a bodyguard.

The explosion shook the building, shattered some windows and caused the partial collapse of an exterior wall, according to the two Iranian officials, members of the Revolutionary Guard briefed on the incident. Such damage was also evident in a photograph of the building shared with The New York Times.

Haniyeh, who had led Hamas’ political office in Qatar, had stayed at the guesthouse several times when visiting Tehran, according to the Middle Eastern officials. All of the officials spoke on the condition of anonymity to share sensitive details about the assassination.

Iranian officials and Hamas said Wednesday that Israel was responsible for the assassination, an assessment also reached by several US officials who requested anonymity. The assassination threatened to unleash another wave of violence in the Middle East and upend the ongoing negotiations to end the war in the Gaza Strip. Haniyeh had been a top negotiator in the ceasefire talks.

Israel has not publicly acknowledged responsibility for the killing, but Israeli intelligence officials briefed the United States and other Western governments on the details of the operation in the immediate aftermath, according to the five Middle Eastern officials.

On Wednesday, Secretary of State Antony Blinken said the United States had received no advance knowledge of the assassination plot.

In the hours after the killing, speculation immediately focused on the possibility that Israel had killed Haniyeh with a missile strike, possibly fired from a drone or a plane, similar to how Israel had launched a missile on a military base in Isfahan, Iran, in April.

That missile theory raised questions about how Israel might have been able to evade Iranian air defence systems again to execute such a brazen airstrike in the capital.

As it turns out, the assassins were able to exploit a different kind of gap in Iran’s defences: a lapse in the security of a supposedly tightly guarded compound that allowed a bomb to be planted and to remain hidden for many weeks before it would eventually be triggered.

Such a breach, three Iranian officials said, was a catastrophic failure of intelligence and security for Iran and a tremendous embarrassment for the Revolutionary Guard, which uses the compound for retreats, secret meetings and housing prominent guests such as Haniyeh.

How the bomb was stashed in the guesthouse remained unclear. The Middle Eastern officials said the planning for the assassination took months and required extensive surveillance of the compound. The two Iranian officials who described the nature of the assassination said they did not know how or when the explosives were planted in the room.

Israel decided to carry out the assassination outside Qatar, where Haniyeh and other senior members of Hamas’ political leadership live. The Qatari government has been mediating the negotiations between Israel and Hamas over a cease-fire in Gaza.

The deadly blast early Wednesday shattered windows and collapsed a portion of the wall of the compound, photographs showed and the Iranian officials said. It appeared to do minimal damage beyond the building itself, as a missile probably would have done.

At around 2 a.m. local time, the device exploded, according to Middle Eastern officials, including the Iranians. Startled building staff members, the officials said, ran to find the source of the tremendous noise, leading them to the room where Haniyeh was staying with a bodyguard.

The compound is staffed with a medical team which rushed to the room immediately after the explosion. The team declared that Haniyeh had died immediately. The team tried to revive the bodyguard, but he, too, was dead.

The leader of the Palestinian Islamic Jihad, Ziyad al-Nakhalah, was staying next door, two of the Iranian officials said. His room was not badly damaged, suggesting precise planning in the targeting of Haniyeh.

Khalil al-Hayya, the deputy commander of Hamas in Gaza who was also in Tehran, arrived at the scene and saw his colleague’s body, according to the five Middle Eastern officials.

Among the people immediately notified, said the three Iranian officials, was Gen. Ismail Ghaani, the commander in chief of the Quds Force, the overseas arm of the Revolutionary Guard, which works closely with Iranian allies in the region, including Hamas and Hezbollah. He notified Iran’s supreme leader, Ayatollah Ali Khamenei, in the middle of the night, waking him up, the officials said.

Four hours after the blast, the Revolutionary Guard issued a statement that Haniyeh had been killed. By 7 a.m., Khamenei had summoned the members of Iran’s Supreme National Security Council to his compound for an emergency meeting, at which he issued an order to strike Israel in retaliation, according to the three Iranian officials.

Tehran had already been under heightened security because of the inauguration of Iran’s new president, Masoud Pezeshkian, with senior government officials, military commanders and dignitaries from 86 countries gathering at parliament in central Tehran for the ceremony.

Haniyeh had looked cheerful and triumphant Tuesday (July 30) during the swearing-in, hugging the new president after he delivered his inaugural speech, and the two men raised their hands together, making the victory sign.

In Iran, the method of assassination was the subject of rumour and dispute. The Tasnim News Agency, the media outlet for the Revolutionary Guard, reported that witnesses said an object like a missile had hit the window of Haniyeh’s room and exploded.

But the two Iranian officials, the members of the guard briefed on the attack, confirmed that the explosion had taken place inside Haniyeh’s room, and said that an initial investigation showed that the explosives had been placed there sometime in advance.

They described the attack’s precision and sophistication as similar in tactic to the remote-controlled artificial intelligence robot weapon that Israel used to assassinate Iran’s top nuclear scientist Mohsen Fakhrizadeh in 2020.

Israeli assassination operations outside of the country are primarily carried out by Mossad, the country’s foreign intelligence service. David Barnea, the head of Mossad, said in January that his service was “obliged” to hunt down the leaders of Hamas, the group behind the Oct. 7 attacks in Israel.

“It will take time, as it took after the massacre in Munich, but our hands will catch them wherever they are,” Barnea said, referring to the killing of Israeli athletes by terrorists at the 1972 Olympics.

-New York Times