WASHINGTON — The war in Iraq is winding down, but controversy over the performance of the Patriot missile system during the conflict is just heating up. According to U.S. Air Force Lt. Gen. Ronald Kadish, director of the Pentagon’s Missile Defense Agency, the system engaged nine incoming missiles from Iraq. Several, he said in testimony April 9 before the Senate Appropriations Committee, were tracked but not fired upon because they were headed toward unpopulated areas.

"Overall, the performance is very encouraging from the standpoint that we seem to have engaged the targets successfully," Kadish said. A combination of Patriot Advanced Capability (PAC) 3 and PAC 2 missiles were fired, he said.

But such tentative government assessments were immediately attacked by Patriot critics demanding more evidence.

"How do we know they intercepted the missiles?" asked Joseph Cirincioni, director of the nonproliferation project at the Carnegie Endowment for International Peace here. "That is exactly the problem we had with the claims of Patriot successes during the 1991 Gulf War."

The Patriot’s performance against Iraqi Scud missiles during that conflict is the subject of enduring controversy. Shortly after the war, the Army reported it shot down 80 percent of Scuds headed for Saudi Arabia and 50 percent of those aimed at Israel. After several independent investigations questioned those figures, the Pentagon lowered its intercept estimates to 70 percent over Saudi Arabia and 40 percent over Israel.

Reliable accounting of enemy missiles engaged during the current conflict, known as Operation Iraqi Freedom has itself been a moving target. According to the Army’s Central Command offices in Qatar, Iraq launched 11 missiles toward Kuwait and nine were successfully intercepted by Patriot batteries. The remaining two missiles were allowed to pass into uninhabited areas of the country.

Industry sources familiar with the Patriot variants currently stationed in Kuwait and Iraq said 19 Iraqi missiles have been fired toward Kuwaiti targets and that 10 of those were engaged successfully. One of the Iraqi missiles apparently exploded on launch and another eight were allowed to fly into unpopulated areas.

"[The PAC 3] hasn’t missed anything it meant to hit," said Army Maj. Rumi Nielson-Green, a spokeswoman for Central Command.

However, Patriot missiles also downed at least two friendly aircraft, with fatal consequences in both cases. On March 22, a Patriot missile downed a British Tornado fighter bomber near the Kuwait border, killing its two pilots. On April 2, a Patriot missile destroyed a Navy FA/18 Hornet near the city of Karbala, also in Iraq. The pilot was killed. There also was a close call March 24 when a Patriot battery locked onto a U.S. F-16 fighter near the Iraqi town of Najaf.

The Army confirmed April 14 that the Patriot batteries were not tasked to defend against enemy aircraft and said the fratricide incidents are under investigation.

"We were a danger to our own people," said Victoria Samson, an analyst with the Center for Defense Information here. "It’s troubling; [the Patriot system] is not supposed to be targeting aircraft. The aircraft up there were all ours."

Military authorities confirmed to Senate Appropriations Committee Chairman Ted Stevens (R-Alaska) during an April 9 hearing that a malfunction of the electronic Identification Friend or Foe (IFF) system was likely a factor in the mishaps. All U.S. military and allied aircraft since the 1950s have carried a special radio beacon which broadcasts a secure identification code to ground radars. The technology has been upgraded many times and is usually highly reliable for aircraft, military experts say.

"It has been heroically dependable," said John Pike, director of GlobalSecurity.org. "The [Patriot] shoot-downs are extremely puzzling."

That isn’t to say accidents haven’t occurred in the past. On April 14, 1994, two U.S. Blackhawk helicopters were shot down in northern Iraq by friendly aircraft. Twenty-six people were killed. After the accident, the Pentagon promised to pursue, among other things, improved IFF systems.

The Patriot system has had its share of problems with IFF. During a two-week field test in 2000 at the Fort Stewart Army base in Mississippi, the missile system fired repeatedly on friendly aircraft during simulations.