Iraq claimed on Wednesday to have shot down an unmanned U.S. aircraft that entered its airspace from Kuwait, but the U.S. military disputed the report, saying it appeared to be untrue.

If the report were confirmed, it would be the second time in a month that Iraqi defenses had brought down one of the American reconnaissance drones.

A spokesman for U.S. Central Command said no Predators -- or any other aircraft operating in the region -- were known to have gone missing.

"As far as I know, everything's accounted for," said Lt. Col. Martin Compton, at the command based in Tampa, Fla.

An unnamed spokesman for Iraq's air defense command, quoted by the official Iraqi News Agency, said Wednesday that the downed aircraft was a Predator but did not say where or when it was shot down.

"The spy plane that breached the sanctity of Iraq's international airspace is used by the American enemy to spy on our civilian and military installations," the spokesman said.

"With a resolve that never fails and with hearts filled with faith in God, country and leader, our brave men in the air defense forces were able to shoot down an American reconnaissance plane from the Predator type that came from Kuwait," the Iraqi agency said.

After Iraq brought down a Predator on Dec. 23, U.S. officials called it a "lucky shot" and did not treat it as a significant hostile act.

In that encounter, Iraqi warplanes penetrated the southern no-fly zone and fired at the $3.7 million Predator, the Pentagon reported. Iraq gave a different version, saying the drone was shot down by ground air defense forces.

American warplanes have been patrolling the skies of southern and northern "no-fly zones" in Iraq since 1991, keeping Iraqi aircraft from flying in those areas.

The camera-equipped Predator drones presumably have been overflying Iraqi territory to reconnoiter for troop movements and other intelligence that would be useful for any U.S. attack resulting from the current international crisis over Iraq's alleged weapons of mass destruction. They may also be looking for information useful in the ongoing U.N. weapons inspectors' hunt for such arms programs.

At low altitude, the unstealthy, relatively slow-moving Predator presents an easy target for air-defense weapons. The Pentagon hasn't released exact details of all Predator crashes, but it acknowledges it has lost about 20 of the aircraft worldwide. "The bulk of those," says an Air Force official, "were lost over enemy territory."

The Iraqi government contends that the U.S.-British air patrols and the concept of "no-fly zones" are illegal under international law, not authorized by any U.N. resolutions. Washington says the no-fly zones were established to protect the country's Shiite Muslim and Kurdish communities after failed rebellions in those areas in 1991, at the end of the Gulf War.

According to U.S. officials, Iraqi air defenses fired on U.S. and British warplanes patrolling the zones almost 500 times last year, but have never shot down a piloted plane since the war.

Gen. Richard Myers, chairman of the U.S. joint chiefs of staff, said last week that Washington offered Predators for temporary duties with the United Nations to do reconnaissance for the weapons inspections effort. He said UNMOVIC, the U.N. inspection agency, thus far had accepted only an offer of higher-flying, manned U-2 reconnaissance aircraft. The Iraqi government thus far has resisted the U.N. plan for U-2 flights over Iraqi territory.