U.S. military officials in Iraq say at least 21 Iraqis have been killed in three attacks north of Baghdad.
In the largest attack, authorities say gunmen in two vehicles opened fire on buses taking Iraqis to work at a U.S. facility in Tikrit, killing 17 civilians and wounding 13 others.
Later, officials say a car bomb killed at least three Iraqi National Guardsmen north of Tikrit. Separately, an Iraqi soldier was killed when a patrol came under attack in Samarra.
In other developments, the U.S. military says its engineers have begun drafting a reconstruction plan for the city of Fallujah. Much of the flashpoint city west of Baghdad was devastated last month in fighting between insurgents and U.S. forces.
Officials say engineers will first move to restore water and electricity, before rebuilding hospitals, schools and solid waste facilities.
Some information for this report provided by AFP and Reuters.