The sound of weeping mothers who lost their sons and daughters in Russia's school siege drifted out of the homes of Beslan yesterday as the first burials were held for some of the 338 people killed.

North Ossetian spokesman Lev Dzugayev said 428 people remained in local hospitals and 260 were unaccounted for. A number of serious cases were taken to Moscow and other cities.

Alina Khubechova celebrated her 11th birthday the day before Chechen separatists seized her school last week. Four days later her grief-stricken parents buried her, grasping a picture of the pretty brown-haired girl with white ribbons in her hair.

The president of North Ossetia, a southern province where the hostage drama unfolded, apologised for failing to avert it.

"I fully understand my responsibility," Alexander Dzasokhov told doctors and relatives of the wounded children in a hospital in the regional capital Vladikavkaz not far from Beslan.

"I want to beg your pardon for failing to protect children, teachers and parents," said the regional leader, who looked distressed with tears in his eyes.

In another sign of officials taking responsibility for the bloodbath, the regional Interior Minister Kazbek Dzantiyev offered his resignation. It was not accepted.

Official accounts say forces moved on the school gymnasium on Friday after Chechen separatists holding 1,000 people hostage started firing on children fleeing in panic from two explosions.

It was the bloodiest end to a hostage crisis in decades. Half the dead were children. The rest were teachers, parents and relatives attending festivities on the first day of term.

The carnage has thrown President Vladimir Putin's policy in the turbulent Caucasus region into disarray and raised serious doubts about whether he can end Chechen separatism. The siege followed bombings aboard two airliners and near a Moscow metro station.

Ambulances that on Friday ferried the injured to hospital, spent yesterday standing by at the funerals to help relatives overcome with grief. Grieving relatives left front doors and windows open, according to local custom.

"Beslan is such a small town," said Zoya, who attended Alina's funeral. "What did we do to deserve all this?"

Others pressed on in search of missing relatives, forced to tour local hospitals in hope, and morgues in trepidation.

Rimma Butueva, a doctor, spent days looking for her cousin Rosa, missing along with her nine-year-old son.

"We did not give up hope until the end," she said. "But when we saw her body we understood we wouldn't find her eldest son. The worst was recognising him by his clothing."

Orthodox churches across Russia held memorial services and Mr Putin declared today and tomorrow days of national mourning.

Mr Putin, a former KGB spy who came to power four years ago promising to stamp out separatism, said the security forces needed to rethink their approach to tackling such emergencies.

Questions have persisted about the storming of the school and how the gunmen managed to transport huge quantities of explosives and ammunition into the school.

Soslan Bidoyev, 23, was shocked by his brother's account of events at the school when it was seized last Wednesday.

"He told us that when the hostages were brought in, the gunmen made the adults pry open the gymnasium floor. They took out supplies of weapons from underneath the floor," he said.

Such accounts strengthened the view that the gunmen were well prepared and had local help, and fuelled the anger of residents who accused Mr Putin of making only a token visit to the town and failing in his duty to protect them.

Valery Andreyev, local head of the FSB security service, was quoted by Moscow radio station Ekho Moskvy as saying the militants may have received help from local police, possibly because they were coerced.