Hamas leader Ismail Haniyeh was killed Wednesday by an explosive device that was smuggled into his guesthouse in Tehran, according to seven Middle Eastern officials, including two Iranians, and one American official.

Five of the Middle Eastern officials said the explosive device was smuggled in about two months ago and had been hidden there. The guesthouse is run and protected by Iran’s Islamic Revolutionary Guard Corps and is part of a large complex known as “Nasha” in an upscale neighborhood in northern Tehran.

Haniyeh was in Tehran to attend the inauguration of Iran’s president. After confirming he was in his room, the bomb was detonated remotely, according to the five officials. The blast also killed a bodyguard.

The blast shook the building, blew out some windows and caused part of the outer wall to collapse, said two Iranian officials, members of the Islamic Revolutionary Guard Corps who were briefed on the incident.photoThese damages can also be clearly seen in the

Haniyeh, who once headed Hamas’s political office in Qatar, had stayed at the guest house several times during previous visits to Tehran, according to the Middle East officials, all of whom spoke on the condition of anonymity to discuss sensitive details about the assassination.

Iranian officials and Hamas said Wednesday that Israel was responsible for the assassination. Several U.S. officials, who also asked not to be named, reached the same conclusion. The assassination threatens to spark a new round of violence in the Middle East and derail ongoing negotiations to end the Gaza war. Haniyeh had been a key voice in ceasefire talks.

Israel has not publicly acknowledged responsibility for the assassination, but according to five Middle Eastern officials, Israeli intelligence officials informed the United States and other Western governments of the details of the operation immediately after it took place.

On Wednesday, Secretary of State Antony Blinken said the United States had no prior knowledge of the assassination plan.

In the hours after the assassination, speculation immediately focused on the possibility that Israel had killed Haniyeh with a missile strike, perhaps fired from a drone or aircraft, with the possibility that the missile had been fired from a drone or aircraft.In April this year, missiles were fired at a military base in IsfahanThe method is similar to .

The missile story raises some questions: For example, how could Israel once again evade Iran’s air defenses and carry out such a blatant air strike on the country’s capital.

In fact, the assassination attempt exploited another flaw in Iran’s defense system: a security loophole in a building that was considered to be heavily guarded allowed the bomb to be placed there and hidden for weeks until it was finally detonated.

Three Iranian officials said the existence of such a security loophole was a catastrophic failure of Iran’s intelligence and national security agencies and a great shame for the Islamic Revolutionary Guard Corps. The building was a rest home for the Islamic Revolutionary Guard Corps, where secret meetings were held and important guests such as Haniyeh were received.

It was not immediately clear how the bomb was placed in the guest house. The Middle Eastern officials said the assassination took months to prepare and required extensive surveillance of the building. The two Iranian officials who described the method of the assassination said they did not know how or when the bomb was placed in the room.

Haniyeh and other senior Hamas political leaders usually live in Qatar, and Israel decided to carry out the assassination elsewhere. The Qatari government has been mediating negotiations between Israel and Hamas on a ceasefire in Gaza.

Aside from damage to the building, which was shown in photos and tore down parts of its walls, the deadly blast early Wednesday morning appeared to have shattered its windows and collapsed parts of its walls, as Iranian officials have said, other damage appeared limited and not likely to be the result of a missile strike.

According to Middle Eastern officials, including Iranian officials, the bomb was detonated at about 2 a.m. local time, surprising the staff in the building. Officials said the staff rushed to find the source of the loud noise, which led them to the room where Haniyeh and a bodyguard lived.

A medical team was stationed in the building and rushed to the room immediately after the explosion. They pronounced Haniyeh dead and tried to revive the bodyguard, but he also died.

Ziad al-Nakhaleh, the leader of the Palestinian Islamic Jihad, lived in an adjacent room, the two Iranian officials said, but his room was not seriously damaged, suggesting that Haniyeh was the target of a precisely planned strike.

Hamas deputy commander in the Gaza Strip, Khalil Haya, who was also in Tehran, went to the blast site and saw Haniyeh’s body, according to five Middle Eastern officials.

Among those notified immediately was Gen. Ismail Ghani, the commander-in-chief of the Quds Force, the overseas arm of the Islamic Revolutionary Guard Corps, which works closely with Iran’s allies in the Middle East, including Hamas and Hezbollah, three Iranian officials said. Ghani woke up Iran’s Supreme Leader, Ayatollah Ali Khamenei, in the middle of the night to brief him, the officials said.

Four hours after the explosion, the Islamic Revolutionary Guard Corps issued a statement saying Haniyeh had died. Three Iranian officials said Khamenei summoned members of Iran’s Supreme National Security Council to his residence for an emergency meeting at 7 a.m. and issued an order to retaliate against Israel at the meeting.

Tehran has stepped up security for the inauguration of Iran’s new president, Massoud Pezeshkian, as senior government officials, military commanders and dignitaries from 86 countries gathered at the parliament building in central Tehran for the inauguration.

Haniyeh looked delighted at Tuesday’s inauguration, hugging the new president after his inauguration speech before both raised their hands in victory signs.

The method of the assassination is a subject of rumor and controversy in Iran. The Islamic Revolutionary Guard Corps-affiliated Tasnim news agency reported eyewitness accounts that a missile-like object hit the window of Haniyeh’s room and then exploded.

The two Iranian officials, members of the Islamic Revolutionary Guard Corps who were briefed on the matter, confirmed that the explosion took place in Haniyeh’s room, but they said preliminary investigations showed that the bomb had been placed there in advance.

They said the precision and sophistication of the attack was similar to the method Israel used in 2020 to assassinate Iran’s top nuclear scientist Mohsen Fakhrizadeh.Remote controlled artificial intelligence robot weapons.

Israel’s assassinations abroad are mainly carried out by the country’s foreign intelligence agency, Mossad. Mossad chief David Baniya said in January that his agency had a “legal obligation” to hunt down leaders of Hamas, which was behind the October 7 attack on Israel.

“It will take time, just as it did after the Munich massacre, but we will capture them wherever they are,” Baniya said, referring to the killing of Israeli athletes by terrorists at the 1972 Munich Olympics.