A car bomb has killed at least eight people and wounded as many as 31 others in the Iraqi city of Najaf, police have said.

Police and hospital officials said the driver of the car detonated his explosive-packed vehicle at a police checkpoint, south of Baghdad on Wednesday morning.

Early reports said that the attack occurred at a police checkpoint in Maydan Square near Najaf's old city.

The area is the holiest site for Shias, and is usually packed with locals and religious tourists.

It also is the site of the headquarters of Grand Ayatollah Ali al-Sistani, the spiritual leader of Iraq's Shias, and Muqtada al-Sadr, whose militia engaged in heavy fighting with US forces in the area in 2004.

Police reinforcements arrived soon after the explosion and sealed off the scene, where blood stains were mingled with charred wreckage.

It was not immediately clear how many police were among the dead.

PHOTO CAPTION

Men carry the coffin of a victim, killed in Sunday's twin bomb attacks, during a funeral in Najaf, south of Baghdad, February 19, 2007. (Reuters)