Coalition aircraft strike Iraq

STUTTGART, Germany (CNN) -- Coalition forces said they bombed Iraqi air defence installations on Tuesday after aircraft enforcing the northern no-fly zone were fired on.

The incident, which the U.S. European Command in Stuttgart said occurred near the Saddam Dam near Ninava, came a day after Baghdad said its forces shot down an unmanned surveillance plane. The Pentagon said the drone did crash, but denied that Iraq had shot it down.

"Coalition aircraft responded to the Iraqi attack by delivering precision ordnance on elements of the Iraqi integrated air defence system," European Command spokesman Capt. Geoffrey Fischer said in a statement.

Coalition aircraft have been patrolling no-fly zones in Iraq since the end of the Gulf War in 1991. Iraqi President Saddam Hussein launched a policy of challenging enforcement of those zones in late 1998, deploying surface-to-air missiles and anti-aircraft artillery against the aircraft.

Marine Cmdr. Ernest Duplessis, a spokesman at U.S. Central Command, said an investigation was under way to learn the cause of Sunday's crash. He said he was not aware of any electronic jamming that could have caused pilots on the ground to lose control.

Four of the $3.5 million advanced surveillance drones have crashed since late last year -- three while deployed by the military in Afghanistan. None has been lost to enemy fire, according to the United States.

The CIA also has been using the Predator around Afghanistan in a configuration that includes weapons that can be targeted and fired by remote control.

The aircraft that crashed Sunday in Iraq was unarmed, and the wreckage has been completely recovered, officials at U.S. Central Command said. But Iraqi media aired footage Monday of what it says was the downed drone.

-- CNN Producer Rym Brahimi in Baghdad contributed to this report.