Four American soldiers have been killed by insurgents in attacks north of Baghdad during the past two days, the United States military said today. A soldier was killed today when a roadside bomb exploded near a vehicle patrol close to Adwar, a town near Tikrit, according to a military statement. Two 42nd Infantry Division Soldiers were killed Tuesday in an attack on their base in Tikrit, and a roadside bomb exploded near another vehicle late Tuesday, killing a soldier attached to the 1st Corps Support Command. Full Story