KUWAIT CITY -- Four U.S. soldiers were killed early Tuesday when their helicopter crashed during night training in the Kuwaiti desert amid a U.S.-led military buildup for a possible war against Iraq, the U.S. Army said.

The UH-60 blackhawk helicopter, one of two from the army's V corps conducting night training, crashed at approximately 1:00 A.M.

(1000 GMT Monday) near Camp New Jersey, about 50 kilometers (30 miles) northwest of Kuwait City, the army said in statement.

The four crew, whose names were being withheld pending notification of next of kin, were the only personnel on board the aircraft.

The cause of the crash is currently under investigation, the army said.