NATO Jets Begin Patrol Over Bosnia : Balkans: American, French and Dutch pilots find no sign of Serbian planes violating ‘no-fly’ zone. Serbs unleash heavy artillery on Srebrenica and Sarajevo.

As NATO warplanes took to the skies over Bosnia-Herzegovina on Monday to begin enforcing a “no-fly” zone, rebel Serbs immediately underscored the limited muscle of the mission by turning their heavy artillery on the town of Srebrenica, killing 35 civilians.

An additional 68 people were wounded in what U.N. Protection Force spokesman John Mills described as an intense, hourlong barrage that took a particularly heavy toll among players at a school soccer field.

Serbian tanks and mounted guns on the hills surrounding Sarajevo also unleashed the heaviest assault on the Bosnian capital in weeks, Mills reported from U.N. headquarters in the Croatian capital of Zagreb.

From air bases in Italy and the decks of carriers in the Adriatic Sea, fighter pilots of three nations launched Operation Deny Flight, the first mission outside the territories of the North Atlantic Treaty Organization’s member nations.

The American, French and Dutch pilots, returning after weaving through glowering clouds over Bosnia, said there was no sign of the Serbian planes and helicopters that have routinely defied the United Nations’ no-fly order in recent months.

One accident marred an otherwise smooth first day of enforcement. A French Mirage fighter suffered mechanical failure and ditched in the Adriatic. The pilot ejected safely and was rescued by a helicopter, said officials at the NATO coordination center at Vicenza in northeastern Italy.

They ruled out hostile action as the cause of the crash.

The no-fly zone had been imposed by the U.N. Security Council last October in a largely symbolic effort to show international condemnation of Serbian aggression. It was given some teeth last month when the council approved enforcement measures, but pilots are under orders to refrain from firing their air-to-air missiles unless violating aircraft ignore repeated warnings to land.

Most of the nearly 500 violations of the air exclusion zone recorded by U.N. monitors since October have been attributed to the Bosnian Serbs, who are the only force with combat aircraft. Some illegal flights from neighboring Croatia have also been observed.

The long-delayed enforcement is meant to show international resolve to halt the year-old Serbian siege of Bosnia, but its immediate consequences have only added to the suffering of the republic’s embattled Muslims and instilled a spirit of defiance among rebellious Serbs.

Fear of Serbian retaliation against Western aircraft prompted the Office of the U.N. High Commissioner for Refugees to suspend relief flights into Sarajevo until at least midweek.

That is expected to worsen the already dire supply situation in Bosnia, where more than half the population depends on foreign food aid.

The U.N. refugee agency also announced from its headquarters in Geneva that food stocks are at a dangerous low and that the massive undertaking to feed nearly 3 million victims of the Balkan war can last little more than a week unless donor countries pledge more funds.

Truck convoys from this Adriatic Sea port to besieged Sarajevo have been stepped up, “but we’ll never be able to make up the difference for the airlift, and we’ve also got pipeline problems,” said refugee agency envoy Karin Landgren, referring to the dwindling aid stocks.

Despite the much-publicized air patrols, the no-fly order is expected to have little influence on the fighting because the focus of the Serbs’ rebellion has been on ground operations. The Serbs have a daunting advantage in artillery provided by the Yugoslav federal army and have used the tanks and mobile guns to encircle coveted territory and pound it into surrender.

In Sarajevo, Gen. Ratko Mladic, commander of the Bosnian Serb forces, met with the top commanders of U.N. forces in the former Yugoslav republics for the second time in less than a week but again refused to allow U.N. soldiers to enter Srebrenica, Mills said from Zagreb.

The Bosnian U.N. commander, French Gen. Philippe Morillon, had proposed stationing 150 Canadian troops in the endangered enclave in the hopes of deterring an all-out Serbian attack on the town and the 60,000 Muslims taking refuge there.

The Bosnian Muslim commander boycotted the Sarajevo meeting in protest of the continuing assault on civilians in Srebrenica.

Mladic and Bosnian Serb leader Radovan Karadzic have made clear they will not back down from their offensive despite the mounting Western pressures to get them to agree to a peace plan drafted by U.N. and European Community mediators.

Karadzic has warned that NATO aircraft could be shot down--a move he professes his rebels would never undertake but that he fears they would be blamed for.

Allied pilots who returned from patrols Monday said they flew low enough to see the farms and cities of the tormented former Yugoslav republic. They said it took only about 15 minutes to fly across Bosnia.

The operation took wing from the Italian base at Aviano in the afternoon when two U.S. Air Force F-15 Eagle fighters draped with Sea Sparrow and Sidewinder air-to-air missiles roared off the runway heading east.

American pilots agreed among themselves not to be quoted by name for security reasons but otherwise freely offered after-patrol reports.

“It was exciting to fly the first mission. It went without a hitch,” said one of the pilots, with the call sign Tooey, a lieutenant colonel from New York state.

“We train daily to perform this type of mission, and it executed very smoothly,” said call sign Conan, a captain from South Carolina.

By late Monday, eight F-15s from Aviano had taken part in the round-the-clock Bosnia patrol, according to Capt. Shawn Mecham, a spokesman at the base. French and Dutch fighters and U.S. Navy aircraft from the carrier Theodore Roosevelt also flew Monday.

In all, about 50 American, French and Dutch fighters will fly from Italian bases and American and French carriers in the Adriatic. Patrolling fighters, their pilots under strict orders not to violate Serbian airspace, will be supported by AWACS surveillance planes over the Adriatic and Hungary and by American KC-135 air tankers for in-flight refueling.

Williams reported from Split and Montalbano from Rome.

Bosnian ‘No-Fly’ Zone

Flight is restricted over all of Bosnia. NATO planes will fly alongside any violators and order them to land. They will be shot down as a last resort.