Large explosions were heard Wednesday night at the U.S. base at Kirkuk (search) airport, and an Iraqi officer said it appeared the blasts were coming from the ammunition dump there.

Fire engines were seen racing into the airport, which is used by the Americans as a base at this northern oil-producing center.

Maj. Gen. Anwar Mohammed Amin, commander of the Iraqi Civil Defense Corps (search) in the area, said the blasts were coming from an ammunition storage site. He had no further details.