Iraqi Warplane Downed by U.S. : Cease-Fire: Bush says other planes violating the temporary truce will also be attacked. White House adds that incident does not constitute resumption of the war.

A U.S. Air Force fighter Wednesday shot down one of two Iraqi warplanes spotted flying near Saddam Hussein’s hometown in violation of a temporary Gulf War cease-fire, American military officials said.

The two Iraqi fighter-bombers were detected in the skies above Tikrit, about 95 miles north of Baghdad, flying in defiance of American warnings that Iraqi combat planes in the air would be fired upon.

President Bush, in Washington, said any other planes found violating the temporary cease-fire will be shot down as well.

“I don’t think that’s likely to happen,” Bush added.

The Bush Administration has also admonished Iraq against using its warplanes to put down Kurdish and Shiite Muslim rebellions raging in parts of the country.

White House Press Secretary Marlin Fitzwater said that the incident--the first air engagement since allied forces defeated Hussein’s army last month--does not constitute a resumption of the war against Iraq.

“We’re not resuming hostilities. We’re not re-engaging,” he said. “We’re simply proceeding with the cease-fire as we outlined it to the Iraqis.”

An American AWACS aircraft detected the two Soviet-made Iraqi SU-22s and dispatched two F-15C fighters to “visually identify” the jets before engaging, the U.S. Central Command in Riyadh said.

The F-15s made no effort to communicate with the Iraqi aircraft but tracked them for three minutes before one of the F-15s fired a Sidewinder heat-seeking missile at one of the SU-22s and hit it at approximately 1:50 p.m., said Maj. Keith Gillett, a spokesman for the U.S. Central Command. The F-15 pilots reported seeing the ejecting pilot’s partially opened parachute moments later, he said.

“The guy was very low, down to about 100 to 150 feet,” one of the pilots told the Associated Press at a U.S. air base. “I don’t think he made it. The chute never blossomed. . . . It crumpled as it hit the ground.”

The other SU-22--known in North Atlantic Treaty Organization terminology as the Fitter--landed before the American aircraft got close enough to shoot, Maj. Gillett said. Neither Iraqi aircraft returned fire, he added.

In Washington, Pentagon spokesman Pete Williams said the pilots were not able to tell whether the SU-22s had been armed and said there was no evidence that either aircraft had engaged in overtly hostile acts.

“The act of flying these aircraft itself is considered hostile,” Williams said.

Fitzwater said that he expects the incident to have a strong deterrent effect.

“Certainly the warning in this case was clear,” he said. “We said that we would not allow fixed-wing aircraft. One went up and one went down. The message is quite clear, and we have every expectation that they won’t try it again, but if they do, we’re still there.”

Both the F-15 and the Fitter normally carry weapons capable of hitting targets beyond the pilots’ ability to see them. Thus, the order to visually identify the Iraqi planes before shooting at them suggests that allied pilots are operating under restrictive guidelines designed to avoid miscalculation, such as the downing of a civilian jet or unarmed plane.

The Pentagon’s Williams said that the Iraqi air force may have wanted to remove the planes from an area in which they could be vulnerable to Kurdish rebels. He added that Iraq also has requested permission from the allies to move fighter aircraft to bases where they could be consolidated and repairs could be made.

It was not clear whether the incident would jeopardize the signing of a formal cease-fire that is scheduled to be drawn up at the United Nations. The Security Council may vote on the document early next week.

The shooting came after American military commanders warned Iraq that the flying of any fixed-wing aircraft would be considered a threat and a violation of the terms agreed to with Iraqi military officials March 3, three days after the Feb. 28 cessation of hostilities ordered by Bush.

To underline the warning, the U.S. Air Force late last week stepped up combat patrols over Iraq.

“We’re letting them know that we need a cease-fire, we need to have an agreement,” Lt. Gen. Charles A. Horner, the Air Force commander in the Gulf region, said in an interview this week, “and that we still own the skies over Iraq.”

In addition to the blanket restriction on the use of fixed-wing aircraft, Bush has warned the Iraqis that they should not use helicopters against the Kurdish and Shiite rebels.

The F-15C type of aircraft that shot down the Fitter did not see very much combat in the Gulf War because it is used primarily against other aircraft, and most of Iraq’s air force either fled to Iran or stayed on the ground. The Pentagon claims to have destroyed in the war 97 of Iraq’s estimated 700 aircraft, with 137 planes seeking refuge in Iran.

Pentagon officials said the Iraqi planes took off from an air base in Kirkuk, a city in Kurdish-dominated territory, and headed southwest, apparently bound for the Sarha air base south of Tikrit.

No open domestic unrest has been reported in Tikrit, birthplace of Hussein and most of his inner circle. But Kirkuk, about 70 miles away, is an oil-producing city that the Kurds claim to have taken. A Kurdish rebel spokesman in London charged that the Iraqis have been bombarding Kirkuk with napalm. The claim could not be verified independently.

A Western diplomat here in the Saudi capital said uprisings have spread to 32 cities in Iraq. The diplomat suggested that Hussein is losing control over parts of the country and will eventually fall victim to a power struggle between the Iraqi army and Hussein’s ruling Arab Baath Socialist Party.

“He is like a man trying to kill 10 fleas with 10 fingers,” the diplomat said. “The place seems to be unraveling.”

Reports of the turmoil in Iraq have been mounting since the end of the war. At the March 3 meeting, Gen. H. Norman Schwarzkopf, commander of U.S. forces in the Gulf, initiated cease-fire discussions with Iraqi military officers at a desert outpost in the U.S.-occupied Iraqi city of Safwan.

At the meeting, and in a follow-up session last Sunday, the Iraqis were told that they would not be allowed to fly fixed-wing aircraft. During the second meeting, the Iraqis specifically requested permission to fly some of those aircraft, but the plea was rejected and they were warned that any planes spotted aloft would be shot down, American officials said.

Pentagon officials said Iraq has continued to fly helicopters and fighter aircraft. Since Tuesday, several helicopters have flown in northern Iraq, with some undertaking combat missions against insurgents, they said. Since Sunday, two PC-7 trainer aircraft, capable of carrying weapons, flew in western Iraq.

“They’ve tried to be sneaky about this, keeping these flights to a minimum,” said a senior defense official.

Times staff writers Melissa Healy and James Gerstenzang in Washington contributed to this article.

ENFORCING THE CEASE--FIRE TERMS

A U.S. Air Force jet shot down one of two Iraqi jet fighters that U.S. military officials said was flying over northern Iraqi in violation of cease-fire terms. One of two Iraqi Soviet-made single-seat SU-22 Fitter jets was downed about 100 miles north of Baghdad. The other fighter landed.