ISIS claimed responsibility on Thursday for a deadly attack that took place in Iran, at a memorial to the slain Iranian Quds force Commander Qasem Solimani.

SITE, a terror monitoring group, reports that the attack resulted in dozens of deaths and hundreds of injuries.

CNN reports that 284 people have been injured and 84 dead.

The deadliest terrorist attack on Iran since the Iranian Revolution.

Ebhrahim Raisi, the Iranian president, said Israel was responsible for the explosions. He warned that the country would be forced to pay a heavy price.

CNN reported that the Israeli Defense Forces had “no comments” to make on this matter.

“It looks like a terrorist act, similar to what we have seen ISIS commit in the past.” As far as we know, this is our current assumption,” said a U.S. government official.