Serbs Ignore U.N. Truce, Send Tanks Into Besieged City : Bosnia: The invasion triggers panic in Gorazde, which U.N. had designated as a protected area. Enclave’s fall could be a crushing blow to Western policy.

Bosnian Serb tanks thundered into the rapidly collapsing city of Gorazde on Sunday, just hours after U.N. officials had proclaimed victory in negotiating a cease-fire with the rebels.

Triggering mass panic in the largest government-held enclave in eastern Bosnia, the Serbian invasion pressed on despite a call by the U.N. Protection Force for more air strikes against Serbian heavy weaponry firing on the city designated a U.N.-protected safe area.

One official told the Associated Press that 21 people had been killed and at least 55 wounded by Bosnian Serbs in attacks that intensified in the afternoon and evening in Gorazde. The casualty report could not be independently confirmed.

The civilian chief of the U.N. mission, Yasushi Akashi of Japan, had announced shortly before the tanks rolled into Gorazde that he had won a cease-fire agreement that would allow deployment of 350 U.N. troops to the region and compel the Serbs to withdraw from a military exclusion zone extending 1.8 miles from the center of the besieged city.

The rapid-deployment force of French, Ukrainian, British, Egyptian and Scandinavian troops had been on standby all day for dispatch to Gorazde, 35 miles east of Sarajevo, but was dispersed after it became clear that the cease-fire was being ignored.

Sunday’s events followed a familiar pattern drawn by Serbian rebels over the last two years of war: Political leader Radovan Karadzic strikes a conciliatory pose in negotiations while his hard-line military chief, Gen. Ratko Mladic, carries on with aggressive actions on the ground.

Over the last week, Serbian gunmen have shot down a British Sea Harrier on a low flyover above Gorazde, taken more than 200 U.N. troops hostage, laid mines around weapons-containment sites and menaced peacekeeping operations in the capital.

Gorazde’s fall, which U.N. military officials now concede could be imminent, could deal a crushing blow to the credibility of the U.N. mission here--as well as Western policy on the Balkans.

The U.N. force’s inability to halt the deadly assault on Gorazde also appeared to be encouraging Western leaders to look for an escape route from the volatile conflict as it seemed poised to escalate out of control.

Akashi had conceded a day earlier that it would be “meaningless” to continue operations in Bosnia unless the Serbian rebels abandoned their strategy of aggression and conquest.

U.S. officials also seem to have sided with those who believe that nothing can be done here but retreat.

Charles E. Redman, the U.S. special envoy to the Balkans, said there is little appetite among U.N.-member countries for changing the current mission mandate to allow broader use of force.

“I don’t hear any of these people asking for a more forceful mandate,” Redman said when asked whether the U.S. government would support a pullout or a toughening of the rules of engagement. “How could they do that? They don’t have the resources. They don’t have the equipment. I don’t want to speak for the U.N. . . . but I think they’re thinking only of a pullout. I don’t think they see a real force mandate as one they could even defend and argue for.”

Late Sunday, the U.N. Security Council, in a non-binding statement, said the 15-member body condemns “the escalating military activities by the Serb forces against Gorazde.” It made no threat of force to enforce its condemnation.

The U.N. commander for Bosnia, British Lt. Gen. Michael Rose, had called on North Atlantic Treaty Organization warplanes to seek out and destroy tanks threatening his troops and terrifying civilians in Gorazde on Sunday, but for the second day running the bombing raids were called off without the jets having fired their payloads.

Akashi ordered the military arm of the mission to halt the bombing raid because he was sure that Bosnian Serb leaders were about to commit themselves to a broad peace settlement, a U.N. spokesman said.

“Mr. Akashi told us that Karadzic had promised him everything but heaven, so we had to call it off,” the official said, referring to the air strike sortie. “At the moment, everything is very confused.”

One U.S. A-10 aircraft was warned off after the U.N. forward air controller on the ground, who had been trying to guide the plane to one tank firing on the city, was forced to take cover inside a building because the Serbian armor began firing at him, a U.N. military source disclosed.

Air strikes were also called off Saturday when bad weather obscured the targets, and the civilian chief of the U.N. mission had vetoed Rose’s request for “close air support” Friday after a British soldier was killed and Serbs intensified their bombardment.

Relief workers were helpless to evacuate or ease the plight of tens of thousands of Muslims fleeing the advance and thronging the U.N. office in desperate hope of rescue, said Kris Janowski, spokesman for the U.N. High Commissioner for Refugees in Sarajevo.

“Panic has broken out all over the city,” Janowski said he was told by four agency staff members trapped in Gorazde.

The staff members estimated the number of people uprooted by the onslaught as high as 30,000, or nearly half the population of the enclave the U.N. Security Council designated a safe area nearly a year ago.

A Gorazde official reported via ham radio that Serbian attacks had intensified after nightfall and that government troops were having to fight hand to hand to hold off the invaders.

“It’s a nightmare here. Civilians who fled are now packed in the center with no place to go. They are sitting ducks,” said Esad Ohranovic, head of the regional governing council. “It’s very difficult to say how long we can go on like this.”

Bosnian Prime Minister Haris Silajdzic bitterly accused the international community of abandoning the victims of Serbian aggression after more than a year of engaging in “this ridiculous farce of protection zones.”

Since NATO planes bombed Serbian positions near Gorazde for the first time a week ago, the rebels have waged a vicious campaign of retaliation and apparently intimidated the U.N. civilian bureaucracy from resorting to force again.

Nineteen of the 200 U.N. soldiers held captive by the Serbs were released after Akashi arrived in the Bosnian Serb headquarters at Pale on Sunday, although the release of all U.N. hostages had been among his conditions for even meeting with the rebel leaders. The majority of the captives remained in Serbian hands even after the putative cease-fire.