In a speech on Monday at a funeral ceremony for the victims of the attack, the deputy commander of the Revolutionary Guards, Hossein Salami, said, “You have seen our revenge before,” according to the news agency Al Ahed, which is run by the pro-Iranian organization Hezbollah in Lebanon. “You will see that our response will be crushing and devastating, and you will regret what you have done.”

The Ahvaz National Resistance, a little-known group with roots among the Arab minority of Iran, claimed responsibility for the attack on Saturday. So did the Islamic State, though the links to that group were ambiguous. It was the worst attack inside the country since an Islamic State-claimed assault on Parliament in 2017.

Ahvaz is the capital of Khuzestan Province in southwestern Iran, where many of the country’s Arabs live. The Islamic State posted a video that it said showed three of its fighters on their way to the attack, according to IRNA. Two of the fighters were speaking Arabic with an Iraqi accent.