Gunmen dressed all in black abducted 31 Shiite men Saturday from their home in eastern Baghdad, an attack police described as targeting suspected criminals, Iraqi officials said. Separate attacks in the capital killed six people, authorities said.

The kidnappings happened early Saturday morning as gunmen stormed houses in the Shiite neighborhood of Sadr City, kidnapping the men, two police officials said.

The officials said they suspect the kidnapped men were involved in prostitution and criminal activities. Some Shiite militias have been involved attacks against suspected prostitutes and stores that sell liquor as a part of their campaign to impose Islamic laws.

Meanwhile, police and hospital officials said three mortar shells landed on houses in Baghdad's southern suburb of Arab Jabour, killing four people and wounding nine. A bomb blast near an outdoor market in northern Baghdad also killed two people and wounded seven, they said.

All officials spoke on condition of anonymity because they were not authorized to speak to journalists.

Iraq sees near-daily bombings and other attacks often claimed by the Islamic State group, which seized about a third of the country last year.