Thousands of Iraqi police and soldiers have launched a major security crackdown in the northern Iraqi city of Kirkuk.

Authorities say they have imposed an indefinite ban on all pedestrian and vehicle traffic in the troubled city. The move is intended to stop the recent wave of increasing violence there.

An Iraqi spokesman said Saturday security forces are sweeping through neighborhoods in Kirkuk. He said they have confiscated hundreds of weapons and arrested an unknown number of suspected insurgents.

Elsewhere, a suicide bomber attacked a police checkpoint in the northern town of Tal Afar, killing 14 people and wounding several others.

The deadly attack was among several across the war-torn country. Despite a heavy security crackdown in Baghdad, officials say at least nine people were killed in and around the Iraqi capital.

A spokesman for the U.S. military, Major General Joseph Peterson, says 4,000 Iraqi police have been killed in action over the past two years, with another 8,000 wounded. Peterson oversees the coalition police training effort.

The U.S. military says Iraqi and coalition soldiers captured 28 suspected terrorists in Baghdad this week, including three so-called "high value" targets. They were not identified.

Some information for this report was provided by AFP, AP and Reuters.