At least 23 people have been killed and more than 25 wounded in a series of gun and bomb attacks across Iraq, including capital Baghdad, Al Jazeera reported on Sunday, citing local authorities.

The most deadly explosions occurred in Taji, 20 km (12 miles) north of Baghdad, where four car bombs exploded, killing at least six and wounding 22.

In a separate incident, an unidentified gunman killed an Iraqi police colonel in the Amel neighborhood in the south of Baghdad. The attack was followed by a car bomb that targeted the police team that arrived to investigate the shooting. A civilian was killed and at least four people were injured, the local authorities said.

In the Tarmiyah district in northern Baghdad, unidentified gunmen attacked an army checkpoint, killing at least two soldiers and injuring one.

In Balad Ruz, northeast of Baghdad, four people were killed and five injured in another car bombing that targeted police in a market place.

In the city of Baquba, northeast of Baghdad, an improvised explosive device killed four policemen and injured two others.

In Kut, which is located about 150 km (93 miles) southeast of Baghdad, a suicide car bomber hit a police checkpoint in a minibus, killing at least three policemen and injuring seven other people.

A car bomb also targeted a Shia shrine in the city of Madaen, located south of Baghdad, killing at least two people and injuring nine others, the local authorities said.