Nine US soldiers were killed in two separate incidents north of Baghdad yesterday in some of the worst ground attacks in months on US forces in Iraq.
The violence comes as American and Iraqi troops are stepping up a three-week old security crackdown in Baghdad aimed at stemming sectarian bloodshed.
Commanders have said insurgents may intensify assaults outside the capital, where more than 90,000 Iraqi and US troops have been deployed for the push.
In the deadliest of the two attacks on US forces, six soldiers were killed and three others wounded by a roadside blast near their vehicles in Salahaddin province, a Sunni Arab insurgent stronghold north of Baghdad, the military said.
In the separate incident yesterday, three US soldiers were killed and one wounded by a blast near their vehicles in Diyala province, northeast of Baghdad.
US commanders are concerned about the increased use by insurgents of a particularly deadly type of roadside bomb which, US commanders say, is made in Iran. The devices have killed more than 170 US soldiers in Iraq since 2004.
More than 3,170 US soldiers have died in Iraq since the US-led invasion in March 2003.
In the latest of a string of attacks against Shia pilgrims streaming to the holy city of Kerbala to mark an important religious event, five pilgrims were killed and 10 wounded by a car bomb in central Baghdad, police said.
At least seven pilgrims were killed in several attacks in Baghdad yesterday. Sunni Arab insurgents frequently attack Shia pilgrims and sites in what US and Iraqi officials say is a campaign to spark a sectarian civil war.