2 U.S. Soldiers Killed, Iraqi Police Investigated

Separately, an Iraqi died and three were injured in a road accident in central Iraq after their lorry was hit by a U.S. army vehicle, as another Iraqi was killed in a central Baghdad explosion.

In an early morning ambush, a U.S. convoy on patrol in Tikrit, 180 kilometers (120 miles) north of Baghdad was hit by a roadside bomb and shot at by unknown attackers, a senior U.S. military official said, according to Agence France-Presse (AFP).

"There is a potential that some of the wounded may pass away from their wounds," the official told reporters in Baghdad .

None of the attackers was killed, and there was no information of any arrests after the ambush, the official said, on condition on anonymity.

Homemade and roadside bombs, the single biggest killer of U.S. military personnel in Iraq , are often disguised in the carcass of a dead animal such as a dog to avoid raising the suspicion of people driving past.

Added to an official Pentagon tally, the deaths raise to 270 the number of U.S. soldiers killed in action since U.S. President George W. Bush declared major offensive against Iraq on May 1.

Another roadside bomb exploded earlier in the day in Baquba, 60 kilometers (36 miles) northeast of Baghdad , as a U.S. convoy passed, police said.

The blast near a gas station, failed to injure any U.S soldiers, but five Iraqis were hurt.