"Those fatalities and two others announced Tuesday brought the U.S. troop death toll in May to 117, making it the deadliest month for American forces this year, and the bloodiest since the battles for Fallouja in April and November 2004, according to icasualties.org, a website that tracks casualties in Iraq. Violence in Diyala has been on the rise even before the Feb. 13 launch of the U.S. troop buildup in Baghdad. U.S. forces have found themselves battling multiple factions, including members of former dictator Saddam Hussein's Baath Party, foreign-led Al Qaeda forces, and Shiite Muslim militias, which the U.S. military says use armor-piercing bombs."