KUALA LUMPUR: The assassination of Hamas leader Ismail Haniyeh was carried out using a bomb planted two months ago in the Teheran guesthouse that he stayed in.
The New York Times reported that the bomb was detonated remotely after it was confirmed that Haniyeh was in the guesthouse. The blast also killed a bodyguard.
Two Iranian Revolutionary Guards members said the explosion shook the building, shattering some windows and caused partial collapse of a wall.
The guesthouse is run and protected by the Islamic Revolutionary Guards Corps and is part of a large compound, known as Neshat, in an upscale neighbourhood in northern Tehran.
Iranian officials and Hamas hold Israel responsible for the assassination and said several United States officials were informed of it.
"The assassination threatens to unleash another wave of violence in the Middle East and upend the ongoing negotiations to end the war in Gaza," they said.
However, US State Secretary Antony Blinken said the US had received no advance knowledge of the assassination.
Initial speculation after the killing of Haniyeh on Wednesday was that it was by a missile fired from a drone or a plane, similar to how Israel had launched a missile on a military base in Isfahan in April.
Iranian officials called the killing of Haniyeh a major intelligence and security failure and a huge embarrassment for the Guards, who use the compound for important events and guests.
Details of how the bomb was placed in the guesthouse are unclear. Officials noted that the assassination planning took months and involved close surveillance, but they did not know how or when the bomb was planted.
Haniyeh was in Teheran to attended the swearing-in ceremony for Iran's new president.