BAGHDAD — An Islamic State suicide bomber killed at least 24 people who had gathered to watch a soccer match in a stadium south of Baghdad this evening, demonstrating the deadly threat still posed by the group as it is slowly being driven back from the territories it controls.

The attack in the Babil province town of Iskandariyah came hours after U.S. officials said they had killed the Islamic State’s No. 2 commander, an Iraqi known by the nickname Haji Imam, in an airstrike in Syria, though there was no immediate reason to believe the incidents were linked.

The bomber struck as trophies were being handed out to teams after a tournament, according to local officials.

Iraq’s Interior Ministry put the death toll at 24 and said an additional 80 people were injured. A Babil police spokesman, Col. Muthanna Harith, said preliminary reports suggested 30 people died.

Among the dead was the head of the local council, and the injured included two senior local figures in Asaib Ahl al-Haq, one of the Shiite militias active on the front lines against the Islamic State, according to Falah Abdul Kareem, the head of the local security council. But most of the victims were spectators who were attending the tournament, he said.

In a statement issued by its Amaq News Agency, the Islamic State said the attack targeted a gathering of Shiite militias, known collectively as Hashd al-Shaabi. It did not mention that the blast took place at a soccer match.

The Islamic State said that more than 60 people died, including a local militia commander, and that nearly 100 were wounded in the attack. The bomber was named as Saifullah al-Ansari, an apparently fake name indicating that he was a local Iraqi or Syrian member of the group. A photograph accompanying the statement suggests he was in his early teens.

“Our knight immersed into their crowds until he detonated his belt, turning them into scattered parts,” the statement said.

The Islamic State has been resorting to suicide attacks with growing frequency in recent weeks as the group’s fighters slowly lose control of territories they had held in some instances since 2014.

More than 50 people died in a suicide truck bombing in the Babil province town of Hilla this month, a week after two suicide bombings targeting Shiite areas of Baghdad killed more than 100. Hilla is a mixed Sunni-Shiite town, but the attacks there have targeted Shiite communities.

First Published March 25, 2016, 10:53 p.m.