A car bomb exploded in Iraq has killed at least 20 policemen in the northern city of Irbil.

The bomber drove his car into a large group of traffic police recruits in the Kurdish city. More than 100 were also injured in the attack.

It coincided with an assault on a police station in Baghdad, which killed at least six on Monday.

Fighters have targeted Iraqi security forces in an upsurge of violence since a new government was formed in April.

In the Irbil attack, the traffic police recruits were gathering for morning roll-call when the bomber raced his car from a nearby building site.

Security forces desperately opened fire, but no one could stop the car from exploding in the middle of the crowd.

Irbil is usually peaceful. The BBC's Jon Leyne in Baghdad says the Kurdish area of northern Iraq has so far escaped the worst of the violence.

In the Baghdad incident, fighters used a car bomb and rocket-propelled grenades in an assault on a police station in the southern Baya area.

Both of Monday's attacks came a day after a bomber killed 23, including six policemen, at a restaurant in Baghdad.

In that blast - claimed by the group of rebel leader Abu Musab al-Zarqawi - the bomber set off his charge as people were having lunch.

The restaurant - near a police checkpoint - was popular with both Iraqi army soldiers and police officers.

PHOTO CAPTION

Wreck of car bomb in Irbil 20 June, 2005