Three US soldiers and an interpreter were killed during a combat operation on Monday, the US military said on Tuesday.

The fighting took place in the volatile province of Diyala, northeast of Baghdad, a military statement said without providing further details about the incident.

The statement also did not disclose the nationality of the interpreter.

The latest death raised the toll of US soldiers who have been killed in Iraq to 4,250 since the U.S.-led invasion in Iraq in March 2003, according to media count based on Pentagon figures.

Diyala province, which stretches from eastern edges of Baghdad to the Iranian border, has been the stronghold of al-Qaida in Iraq network and other insurgent groups since the outbreak of the war.

(Xinhua News Agency February 24, 2009)