ISTANBUL

Hamas leader Ismail Haniyeh was assassinated early Wednesday in Tehran, with varying reports emerging about the method of the attack.

The New York Times revealed that an explosive device, smuggled and hidden by Israeli spy agency Mossad in Haniyeh's residence for about two months, was detonated remotely after confirming his presence.

The daily said the "explosive device was covertly smuggled into the Tehran guesthouse," run by Iran's Islamic Revolutionary Guards Corps (IRGC), and hidden for about two months, according to seven Middle Eastern officials, including two Iranians, and an American official.

"The bomb was detonated remotely" after confirming Haniyeh's presence in his room, five officials claimed.

The blast caused severe damage to the building, including the partial collapse of an exterior wall, and shattered windows, according to two Iranian officials.

Axios corroborated that Mossad operatives were behind the assassination, reporting that a high-tech device using artificial intelligence was used to kill Haniyeh.

It cited two sources with knowledge on the issue, reporting that Israeli operatives learned which facility and which exact room Haniyeh was staying in during his visits to Tehran.

According to the news website, the bomb was planted in the room in advance and detonated remotely by Mossad operatives who were on Iranian soil after receiving intelligence that Haniyeh was in the room. It reported that Iran's Islamic Revolutionary Guard Corps (IRGC) opened an investigation into the incident.

On the other hand, Iranian news agency Farsnews attributed the attack to Israeli operatives but said the residence was struck by a projectile.

The attack, which also killed one of Haniyeh's bodyguards, targeted the fourth-floor apartment in the Zafaranieh area, it added.

Initial investigations confirmed that the operation was orchestrated by the Israeli regime, reported Farsnews.

It also said Iran's Islamic Revolutionary Guard Corps (IRGC) has labeled the incident "a terrorist act by the Zionist regime."

The Middle East Eye news website reported Friday that three individuals who were in the heavily guarded building where Haniyeh was assassinated claimed that he was killed by a projectile fired at his room and not a planted bomb.

The outlet quoted an individual who stayed in a room near Haniyeh's as saying: "This was definitely a projectile and not a planted bomb." The source reportedly added that the aftermath of the explosion also seemed to suggest a missile attack.

The other two individuals, staying on separate floors, also witnessed the scene after Haniyeh's assassination, including the partial collapse of the ceiling and exterior wall of Haniyeh's room, according to the report.

A source close to officials in the Iranian presidency reportedly told Middle East Eye that the building where Haniyeh and several other Palestinian guests were staying was situated near Tehran's Saadabad palace and guarded by the IRGC.

Haniyeh was assassinated on Wednesday in the Iranian capital, Tehran. While Hamas and Iran blamed Israel for the killing, Tel Aviv has not confirmed or denied its responsibility.

The assassination came a day after Hezbollah commander Fuad Shukr was killed in an Israeli airstrike in Beirut’s southern suburb.

Fears have grown about a full-blown war between Israel and Hezbollah amid an exchange of cross-border attacks between the two sides.

The escalation came against the backdrop of a deadly Israeli onslaught on Gaza which has killed nearly 39,500 people since last October following an attack by Hamas.