Four American troops were killed by hostile fire in the volatile Anbar province, the military said yesterday, the largest number of American deaths in a single attack in more than a month.

The three Marines and one sailor died Sunday, raising to nine the number of US troops who died this weekend. At least 2,337 American service members have been killed since the Iraq war started in March 2003, according to an Associated Press count.

The U.S. military statement did not provide more details about the deaths of the US troops in Anbar. It was the largest number of Americans killed in an attack since Feb 22, when four soldiers were killed by a roadside bomb near Hawija, 150 miles north of Baghdad.

The US military also said two American pilots were killed Saturday when their Apache helicopter crashed during combat operations southwest of Baghdad, adding that the aircraft was probably shot down.

Two soldiers also were killed by a roadside bomb late Saturday in central Baghdad and another died of non-hostile related injuries suffered the same day near the northern city of Kirkuk, according to the US command.