Hundreds of children, their parents and teachers died in the bloody culmination of a 52-hour siege that began when heavily armed Muslim guerrillas stormed their school Wednesday and ended in an hours-long battle with Russian troops Friday.

The battered, burned and scorched survivors of Beslan's School No. 1, many of them half-naked children, filled the region's hospitals as troops continued to fight through the afternoon with guerrillas holed up inside the school. Twenty-seven of the fighters, described as Chechens, Russians, Ingush and Arabs, were killed, and at least three were captured, officials said.

Only by late Friday did the scale of the bloodshed in this small town in the region of North Ossetia, west of war-torn Chechnya, become clear. A top Russian official admitted what anguished relatives had been saying for days: There had been more than 1,000 hostages inside the school, the majority of them children.

Between 500 and 700 injured former hostages were hospitalized Friday, more than 300 of them children, according to varying official accounts. Hundreds were still unaccounted for, though officials acknowledged early Saturday that the death toll would exceed 250.

The worst carnage, according to escaped hostages and rescuers, came at the start of the pitched battle just after 1 p.m. Friday, when the guerrillas exploded the bombs they had rigged inside the school's cavernous gym. The children had been held there without food or medicine, and scores perished when the gym's roof fell on them.

"The whole floor is covered in bodies," said Alan Karayev, a local sumo wrestler-turned-volunteer who entered the gym to recover the children's remains. "There is no ceiling at all. The roof all fell down on the children."

Their school turned into a battlefield, those hostages who could fled. "Many, many dead. Many dead children," said a young boy who said he had been blown out of a window by an explosion. He was distraught but apparently uninjured, flanked by his wailing grandmother.

President Vladimir Putin, whose only comment during the siege had been a pledge to "save the life and health of those who became hostages," remained silent throughout the long afternoon's battle and into the evening as Russians took stock of the losses. In the middle of the night, he visited Beslan and called the attack "inhuman and cruel." The whole country, he told local leaders, is "feeling your sorrow, thanking you and praying for you."

World leaders, including President Bush, offered condolences as they absorbed what Bush called "another grim reminder" of the brutal tactics used by terrorists.

Russian officials said the battle was started by the guerrillas and denied any intention to launch a rescue attempt, a tactic Putin had ordered two years earlier during a Moscow theater siege that resulted in 129 deaths. "We didn't expect this to happen," said Aslanbek Aslakhanov, Putin's top aide for Chechnya, who flew to Beslan on Friday to participate in negotiations that never took place. "What has happened today you know yourselves was started by terrorists."

The siege of School No. 1, attended by 6- to 16-year-olds, began just after 9 a.m. Wednesday when the guerrillas blasted their way into the building at the end of the opening-day assembly. Though Russian officials never confirmed it publicly, the hostage takers demanded the withdrawal of Russian troops from Chechnya and the release of prisoners taken after a guerrilla raid this summer in the neighboring region of Ingushetia. They also demonstrated their seriousness by mining the school with explosives and threatening to blow it up if Russian forces moved in on them.

For 52 hours, that didn't happen.

Then came what looked to be progress midday Friday, when the hostage takers agreed to allow Russians to collect several bodies -- how many remains unclear -- of adults killed in the initial shootout. At 1 p.m., four doctors from the Emergency Situations Ministry arrived to do so.

Instead, a battle erupted.

First, two powerful explosions from inside the building rocked Beslan. Soon, scores of hostages started fleeing, some of them dodging gunfire from the guerrillas. "When the children ran, they began to shoot them in their backs," said Putin aide Aslakhanov.

"Bandits opened fired on the escaping children and adults," said Valery Andreyev, regional head of the Federal Security Service. "To save their lives, we retaliated." In the chaos, some of the hostage takers also tried to escape, officials said.

After initial confusion, the Russian attack began. Helicopters roared overhead, special forces stormed the building, tanks swerved into position. Many of Beslan's anxious fathers also ran toward the school, some armed, some not -- intent only on rescuing their children.

Amidst the shooting, many young hostages, most of them barefoot and almost naked after three days in the withering heat of their gym-turned-prison, ran or limped or were carried to safety. Those still standing gulped bottles of water handed to them by rescue workers. "They're killing us," a young girl on a stretcher told a police officer. "They're exploding everything."

At the local House of Culture, where parents had held vigil for three long days, women cried and hugged each other as the sounds of the nearby battle sank in. One of them screamed, "Why? Why?" No one had an answer.

By 2:30, a traffic jam of ambulances crowded outside the school, and civilians turned their Zhigulis and Ladas and BMWs into rescue vehicles, as well. There were nowhere near enough. Many of the injured were bloodied and burned and covered in dirt. A man came out carrying a naked girl, her hair matted, her body streaked with shrapnel cuts, her head lolled back. He laid her on the ground and tried to revive her. When she didn't respond, he started to cry.

The rescue operation was interrupted by a new round of shooting, right near the line of makeshift ambulances. Rocket-propelled grenades and gunfire from automatic rifles sent the volunteers retreating a block farther from the school, and it was there that four children's corpses soon appeared, laid out under bloodstained white sheets. Several parents came up and looked under the sheets, searching. Then an old woman in a torn flowered dress was brought out on a stretcher, also dead, and rolled onto the grass next to the four children.

"Are there dead children? Where are the dead children?" a woman shouted as she ran up to inspect the bodies. She was looking for her 12-year-old nephew but did not find him there.

Across the railroad tracks that divide Beslan, the scene at the hospital was bedlam. The courtyard was crowded with rank upon rank of stretchers with injured and dazed children. Hundreds of relatives clamored to inspect the handwritten lists of the wounded.

Through it all, the battle with the remaining guerrillas continued. Some apparently remained inside the school well into the evening -- eight, according to the Russian news agency Interfax. Others escaped and fought elsewhere in Beslan with Russian troops. As night fell, the school's gym was still smoldering, its massive windows blown out. The walls inside were pocked with bullet holes and echoed with periodic gunfire and explosions.

Only well after 11 p.m. did Russian officials announce an end to the battle. "Resistance of the terrorists has been fully suppressed," said a statement from the emergency headquarters.

The Kremlin kept tight controls on information during the crisis, failing to give accurate counts of the hostages, confirm the demands made by the hostage takers or describe the identity of the guerrillas.

When the battle began, Russian networks did not broadcast live for more than half an hour. When they went on the air, they avoided reporting any information except from official sources, which later proved inaccurate. Within three hours, all three Russian networks had dropped the story to return to regularly scheduled entertainment programs.

The school seizure capped an already deadly week of terror across Russia blamed on Chechen separatists, with the nearly downing of two airliners and a suicide bombing at a Moscow subway station that together claimed 100 lives.

From the start, relatives in Beslan feared mass fatalities, remembering the outcome in previous hostage-takings in Russia, such as the 2002 Moscow theater siege and the takeover of a hospital in 1995. In a sign that Russian authorities were considering a different course, however, government mediators reached out to Chechen separatist leaders for the first time in years to help resolve the crisis.

In the past, Putin has refused to negotiate with the Chechen rebel government-in-exile, led by Aslan Maskhadov, instead calling the separatists terrorists and resisting efforts to hold peace talks.

But just two hours before Friday's battle broke out, the president of North Ossetia, Alexander Dzasokhov, and another politician telephoned Chechen leader Akhmed Zakayev in London. Zakayev, who represents Maskhadov, said in an interview that they wanted his assistance "because the demands of the hostage takers were directly related to the situation in Chechnya." He told them he was ready to fly to Beslan and try to "convince these people that through such acts Chechnya will never become independent."

The two mediators thanked him and said they would be back in touch in two hours to talk specifics, a follow-up phone call made moot by the battle.

The guerrillas reportedly represented another Chechen faction and were led by Ingush fighter Magomet Yevloyev, who went by the code name "Magas." Yevloyev allegedly worked in close connection with Chechen rebel leader Shamil Basayev, and he was also blamed by Russians for a raid on police posts in Ingushetia this summer that killed more than 90. Estimates on the number of rebels in the school had varied from less than 20 to 40 or more, though when it was over, officials said they had killed 27.

Russian officials have long claimed that Chechen rebels were connected to international Islamic fighters, including al Qaeda. Late Friday, they announced that 10 of the dead guerrillas in the school siege were Arabs, and state television showed video from inside the building showing several dead fighters who appeared to be foreign.

Glasser reported from Moscow. Special correspondent Yulia Solovyova contributed to this report.

A volunteer carries a small child away from School No. 1 in Beslan, near the border with Chechnya, after Russian forces stormed the building.A boy runs for cover after being released from School No. 1 during the battle between Russian forces and the guerrillas who had seized the building.In an image taken from television, released children, above, drink water given to them by rescue workers. Many were barefoot and near-naked because of the stifling heat in the gym where they had been held.A video image shows an Interior Ministry officer carrying an injured child away from the school. More than 1,000 people had been held hostage in the building, most of them children.A mother reaches up to her daughter. Both had been held hostage in the siege.