Early Saturday, 531 people remained hospitalized, including 283 children — 92 of the youngsters in "very grave" condition, health officials said.
Sixty-two hours after the hostage drama began during a celebration marking the first day of the school year, the Russian government said resistance had ended.
Russian President Vladimir Putin made a surprise visit to the town early Saturday and ordered the borders of North Ossetia, the republic where the school is located, closed while any hostage takers still on the loose are pursued.
Valery Andreyev, Russia's Federal Security Service chief in the region, said 10 Arabs were among 27 militants who were killed. The ITAR-Tass news agency, citing unidentified security sources, reported the hostage-taking was the work of Chechen warlord Shamil Basayev, who had al Qaeda backing.
Alla Gadieyeva, 24, who was taken captive with her 7-year-old son and mother, said the militants displayed terrifying brutality from the start. One gunman, whose pockets were stuffed with grenades, held up the corpse of a man just shot in front of hundreds of hostages and warned: "If a child utters even a sound, we'll kill another one."
When children fainted from lack of sleep, food and water, their masked and camouflaged captors simply sneered, she said, adding that adults implored children to drink their own urine in the intolerable heat of the gym.
She and other hostages said there was a little water but no food the first day. The hostages got nothing to eat or drink after that.
Gadieyeva told of three days of unspeakable horror — of children so frightened they couldn't sleep, of captors coolly threatening to kill off hostages one by one. The gym where they were held was so cramped there was hardly room to move.
"We were in complete fear," said Gadieyeva, who spoke to an Associated Press reporter as she lay collapsed with exhaustion on a stretcher outside a hospital. "People were praying all the time, and those that didn't know how to pray — we taught them."
The Interfax news agency quoted unidentified sources in the regional Health Ministry as saying more than 200 people were killed. The figure could not be confirmed. Reporters said they had seen at least 100 bodies in the school gym.
CBS News Correspondent Elizabeth Palmer reports the Russians insist they'd never planned to storm the building, claiming they were still negotiating when one of the hostage-taker's bombs suddenly went off.
Under a grove of trees outside the school, white sheets covered dead bodies, including those of children, on lines of stretchers. Grieving parents and loved ones knelt beside the dead, some of whom were awaiting identification. Nearby, anxious crowds gathered around lists of injured posted on the walls of the hospital buildings.
It was not clear where the tragic end to the siege would leave Putin's tough policy on Chechnya, which has enjoyed broad domestic support despite the heavy toll rebel violence has taken in recent years. He has said the Russian fight in the Caucasus was part of the world's larger war on terrorism.
On his visit to Beslan, Putin warned against letting the attack stir up tensions in the mult-ethnic North Caucasus region. "One of the goals of the terrorist was to sow ethnic enmity and blow up the North Caucasus," Putin said. "Anyone who gives in to such a provocation will be viewed by us as abetting terrorism."
On the campaign trail in Wisconsin, President Bush said the hostage siege was "another grim reminder" of the lengths to which terrorists will go. World governments joined Washington in condemning the militants.
"It is hard to express my revulsion at the inhumanity of terrorists prepared to put children and their families through such suffering," British Prime Minister Tony Blair said.
The State Department issued a public announcement warning U.S. citizens living or traveling in Russia against going to Chechnya and the neighboring regions because of a heightened risk of terrorist attacks.
"American citizens in Russia should exercise caution and remain vigilant and aware of these heightened risks when planning use of or using any form of public transportation. American citizens should also avoid large public gatherings that lack enhanced security measures," the announcement said.
The Arab presence among the attackers would support Putin's contention that al Qaeda terrorists were deeply involved in the Chechen conflict, where Muslim fighters have been battling Russian forces in a brutal war of independence on and off for more than a decade. ITAR-Tass said Basayev received funding for the attack from alleged al Qaeda operative Abu Omar as-Saif.
Russian authorities said they stormed the building after the militants set off explosions and fired shots as emergency teams approached to collect the bodies of several men killed earlier. They said the hostage-takers had given them permission to take the corpses away. Witnesses quoted by Russian media said the militants opened fire on fleeing hostages and then began to escape themselves.
A police explosives expert told NTV television that the commandos stormed the building after bombs wired to basketball hoops exploded in the gymnasium, where many of the children were being held. A captive who escaped told NTV that a suicide bomber blew herself up in the gym.
Channel One TV reported three of the attackers were arrested after trying to escape in civilian dress. Four militants were believed to have escaped. A member of an elite security unit died saving two young girls, ITAR-Tass reported.
The standoff was declared at an end hours after commandos began their midday assault, when a final large explosion issued from the school, apparently ending a gunfight between three militants trapped in the school basement and security forces trying to free children being used as human shields. Sporadic shooting continued hours later.
A hostage who escaped told the AP that the militants numbered 28, including women wearing camouflage uniforms. The hostage, who identified himself only as Teimuraz, said the militants began wiring the school with explosives as soon as they took control. He, too, said they had placed bombs on both basketball hoops in the gym.
The bomb expert said the gym had been rigged with explosives packed in plastic bottles strung up around the room on a cord and stuffed with metal objects.
The militants, some with explosives strapped to their bodies, stormed the school in Beslan on Wednesday morning and kept the hundreds of children along with parents in the sweltering gymnasium, refusing to allow deliveries of food and water.
"They didn't let me go to the toilet for three days, not once. They never let me drink or go to the toilet," Teimuraz said.
Leonid Roshal, a pediatrician involved in negotiations with the militants before they were stormed, called them "very cruel people ... a ruthless enemy."
"I talked with them many times on my cell phone, but every time I ask to give food, water and medicine to the hostages they refuse my request," Roshal said.
Putin's adviser on Chechnya, Aslanbek Aslakhanov, said security forces had not planned to storm the building, but were prompted to move by the first explosions about 1 p.m. Friday. Officials had pledged not to use force.
Russian forces had held back, perhaps remembering the deadly outcome two years ago when security troops pumped nerve gas into a Moscow theater before storming in to free about 800 hostages being held by Chechen terrorists. The nerve gas debilitated the captors but also was the cause of most of the 129 hostage deaths.
As the captives escaped the school, residents and troops ran through the streets, and the wounded were carried off on stretchers. An AP reporter saw ambulances speeding by, the windows streaked with blood. Four armed men in civilian clothes ran by, shouting, "A militant ran this way."
Streets around the school were a dizzying tableau of chaos as soldiers and men in civilian clothes carried children — some naked, some clad only in underpants, some covered in blood, some bandaged. Women, newly freed from the school, fainted.
The children drank eagerly from bottles of water given to them once they reached safety. Many of the children had removed their clothing because of the stifling heat in the gymnasium.
"I am helping you," a man dressed in camouflage told a crying girl. Women gathered around, trying to soothe her, saying "It's all right. It's all right."