June has been the deadliest month for U.S. troops in Iraq since May 2009.
Twelve Americans have been killed during combat operations during this month. All but one were killed in combat
A total of 4,465 U.S. military personnel have died in Iraq since 2003, according to a count conducted by The Associated Press.
Most were killed in Baghdad and southern Iraq where Shiite militias are becoming more active.
Officials say that points to dangers ahead as the U.S. moves to withdraw its forces by the end of this year.