The number of U.S. soldiers killed in Iraq since American forces invaded that country almost two years ago has topped 1,500.

U.S. news agencies put the tally at 1,502 on Thursday. The latest U.S. Defense Department toll was 1,494, but the official tally sometimes lags behind the actual total.

Also Thursday, the Pentagon said the casualty rate for U.S. troops in Iraq for February was the lowest it has been for several months. Spokesman Lawrence Dirita attributed the lower losses to improved intelligence, Iraqi security forces, and increased Iraqi opposition to the insurgency. He added that insurgents may be shifting their targets, attacking more Iraqis and fewer coalition troops.

Meanwhile, Iraq's interim government extended a state of emergency until the end of this month, and insurgent car bombs killed five Iraqi police outside the Interior Ministry in Baghdad.