Iran declared on Wednesday, declared three days of mourning following the killing of Hamas chief, Ismail Haniyeh in Tehran in an attack blamed on Israel.

“The Islamic Republic of Iran announced three days of public mourning following the martyrdom of Ismail Haniyeh,” the government said in a statement.

Hamas spokesperson had confirmed that Haniyeh was hit directly by a rocket in the room where he was staying in Tehran, and that Hamas’ military wing the Al Qassam Brigades would not let the killing “go unaccounted for.”

Earlier in the day, Iranian state media reported that Haniyeh was killed by an “airborne guided projectile,” though it was unclear what form that took.

Speaking at a press conference in the Iranian capital, al-Hayya said Israel would “pay the price for heinous crime” of assassinating Haniyeh.

Israel has not claimed responsibility for Haniyeh’s death