A US soldier was killed in a bomb blast that targeted a convoy north of Baghdad on Sunday, a US military statement said, taking the number of American soldiers killed in recent days to six. "One US coalition soldier died of wounds sustained when an improvised explosive device detonated in Salaheddin province," the statement said. "The soldier was in a convoy when the vehicle has hit." The latest deaths bring the total number of US casualties since the March 2003 invasion to topple Saddam Hussein to 4,272, according to an AFP count based on the independent website icasualties.org. Five US troops were killed on Friday in the deadliest attack on American forces in Iraq for more than a year when a suicide truck bomber struck a police compound in the northern city of Mosul.