The televised statement, which reiterated a call for retaliation, said a rocket with a seven-kilogram warhead was used to target the residence of Hamas’ political leader in the capital Tehran on Wednesday, adding it caused heavy devastation.
It didn’t share details of the residence’s location.
“The action was designed and carried out by the Zionist regime and supported by the US,” said the Guard’s statement.
It added that “the warmongering and terrorist Zionist regime will receive harsh punishment in the suitable time, place, and capacity.”
The assassination has sparked fears of a wider regional conflict and of a direct confrontation between Israel and Iran if Tehran retaliates.
In April, Iran launched hundreds of missiles and drones at Israel, which said it intercepted 99 per cent.