By Lee Keath The Associated Press

BAGHDAD – A fire broke out at an ammunition depot at a U.S. base in southern Baghdad yesterday night, setting off a series of explosions from detonating tank and artillery shells that shook buildings miles away. The U.S. military said there were no immediate reports of casualties.

It was not clear whether the depot at Forward Operating Base Falcon was hit by an attack. The cause of the fire was not immediately known, said Lt. Col, Christopher C. Garver, a military spokesman.

Explosions from detonating tank and artillery ordnance and small-arms ammunition stored at the site went off for hours afterward.

Large flames and smoke rose from the region, and flashes from the blasts and showers of sparks were visible on the horizon visible several miles away in central Baghdad, where the force of the blasts could be felt. The blasts came at time sporadically, at times in rapid succession, lasting into the night. Helicopters were seen in the night sky flying over the area.

The blaze broke out in an ammunition holding area, where material is kept temporarily before distribution to the units at Falcon, said Lt. Col. Jonathan Withington, a spokesman at the base. He said more than three battalions are located at the base but he would not give a specific number of troops.

“There is a lot of ammunition there, but it’s not a full storage depot,” he said. “This does not degrade our operational ability at all.” He would not give exact figures on the amount of ammunition or the number of troops at the base, saying only that “more than three battalions” were stationed there at the time of the fire.

“There is an investigation into the cause of the fire,” he said.

Falcon is located in a former commercial trucking depot in a sprawling industrial area at the southern entrance of Baghdad, near the violence-torn district of Dora, where U.S. troops have been focusing in a 2-month-old sweep of the capital neighborhood-by-neighborhood aimed at rooting out militants and weapons.

Iraqi military officials said no evacuations of residents were ordered from the Dora area.

Iraqi Interior Minister Jawad al-Bolani went on television to reassure residents of the capital.

“The situation is under control,” he said. “There is an alert to security forces to provide any help to the residents of the area. We are waiting for information from the Americans” on the cause, he said