U.S. military deaths in Iraq have fallen in May to the lowest monthly level in more than four years.
Officials said 21 American troops have been killed this month, four of them in non-hostile incidents. That's one more than the lowest monthly figure of the war, set in February 2004.
Civilian casualties were down sharply, too. At least 522 Iraqi civilians and security troopers were killed this month, according to figures compiled by The Associated Press from Iraqi police and military reports. That's down sharply from April's figure of 1,080 and the lowest monthly total this year.
The improvement came as Iraqi forces assumed the lead in offensives in three cities and a truce with Shiite extremists took hold.
But U.S. commanders warned that the relative peace was fragile because no lasting political agreements have been reached.