A suicide bomber struck a funeral gathering in Baghdad on Saturday, killing at least 35 people and wounding more than 60, Iraqi police and hospital officials said.

The attack in the Shaab neighborhood occurred around lunchtime, the officials said, speaking on condition of anonymity because they were not authorized to brief the media. ISIS claimed responsibility in a statement carried by its Aamaq news agency.

Hussein Khazem, the owner of clothing warehouse near where the bombing took place, said the bomber detonated his payload inside a funeral tent, causing a big explosion.

He saw a large number of killed and wounded people, many burning cars and major damage to the local market nearby. The dead included elderly people, children, and some women. He closed his shop to help evacuate the wounded and remove the bodies.

"The security situation is not good at all," he said. "These big incidents are happening again, especially in the poorer residential neighborhoods."

The attack comes as Iraqi security forces are preparing for an operation to retake the militant-held northern city of Mosul, the country's second largest, from ISIS.

In the past, the extremists have increased insurgent attacks inside government-held territory far from the front lines after suffering territorial losses on the battlefield.

Iraq has seen several bombings in recent months, though most have had lower death tolls than Saturday's attack. In July, a massive car bomb in central Baghdad's popular shopping district of Karradah killed about 300 people and forced the resignation of the interior minister.