The U.S. military in Iraq says a sustained series of explosions lasting several hours was part of its anti-insurgent operation in and around Baghdad.
It sounded like a massive firefight somewhere southwest of Baghdad, waking residents in the middle of the night.
No blasts could be seen from the roof of a hotel in central Baghdad, but scores of artillery explosions were clearly audible, as was the roar of heavy machine-gun fire.
A U.S. military spokesman would give few details on what he called an ongoing operation. He said it was related to Operation Iron Justice, which is aimed at cracking down on insurgents and criminal activity in Baghdad. He said the overnight activity involved ground fire and air support.
Once daylight came, residents of neighborhoods near the scene said U.S. helicopter gunships had fired rockets and machine guns. But they also said no obvious targets had been hit, and most of the fire seemed to concentrate on uninhabited areas.
Military sources have indicated the show of force was aimed at deterring attacks over the Christmas period.