The people of the southern Russian town of Beslan began three days of remembrance Thursday to mark the anniversary of a school siege by separatist fighters that left 331 people dead and a community in ruin.

Stepping through the blackened shell of Beslan School No. 1, thousands of people were shown on television as they carried roses and candles into the gymnasium where more than 1,000 hostages were herded on the first day of school last year. Portraits of the dead, 186 of them children, were displayed on the red-brick walls, and mourners leaned their heads against the pictures and sobbed and prayed.

But the anguish was accompanied by rancor because the survivors blame their government, and sometimes each other, for the high death toll in the country's worst terrorist act. Russian President Vladimir Putin stayed away after some relatives of the dead said he was not welcome.

Many Beslan residents express anger about the lack of information and details on official investigations in the year since the attack. Two commissions have yet to report their findings, and residents have little faith in those bodies' ability to assign blame or answer central questions.

In one indication of the public's anger, the former principal of the school, Lydia Tsaliyeva, a hostage during the siege, had to be protected by security officials when she attempted to lay flowers in memory of her murdered students. Some residents blame Tsaliyeva, 73, and the teachers who survived for not doing enough to save their children.

The siege by Chechen separatists ended after 52 hours on Sept. 3 in circumstances that are still in dispute. An explosion detonated in the gym, where heavily armed guerrillas had strung bombs above and among the huddled hostages. The attackers were demanding the withdrawal of Russian forces from Chechnya, the neighboring southern region.

One surviving attacker has claimed during his ongoing trial that the explosion was triggered by a Russian sniper who shot one of the assailants standing with one foot on a bomb trigger; government prosecutors have dismissed that claim. After the initial blast, a chaotic gunfight ensued and fire raced through the building as hostages were killed by shrapnel, bullets, flames and falling debris.

Government critics in Beslan ask how a large group of guerrillas could have passed unnoticed through the area, which has numerous police checkpoints. Others question whether the government employed excessive force, including tanks and flamethrowers, adding to the death toll. In addition, many residents want to identify authorities responsible for what they consider a botched response after the first explosion.

Officials dismissed as "total nonsense" a claim made this week by a Chechen warlord, Shamil Basayev, that the attackers secured free passage to Beslan in an elaborate ruse. Basayev said the Russians had planted an agent in his group who became a double agent and then fooled the Russian security services into thinking the attack would occur in the regional capital of Vladikavkaz on Sept. 6.

Basayev, in comments published on a Web site that often carries his statements, said Russian officials allowed the group to move freely, thinking they were on a reconnaissance mission.

One group of victims and relatives said the government may never provide an accurate version of events.

"We have been waiting patiently for nearly a year for words of truth about the savage murder of our relatives and for the day when the perpetrators are brought to account," the group said in a statement. "However, time and the authorities have shown us that the truth will never be spoken, because it is absurd and horrible. What happened with the hostages was like cattle to the slaughter. The majority of those killed were blown up, shot by tanks or grenade launchers or burned by flamethrowers."

Taimuraz Mamsurov, the president of the Russian republic of North Ossetia, where Beslan is located, said in an interview with reporters that Russian forces had acted "abominably." Two of Mamsurov's children were among the hostages and were wounded.

"As a man, as a father, as a resident, as a leader, as an Ossetian, we all should feel guilt," he said Wednesday.

Putin was scheduled to meet Friday at the Kremlin with representatives of the Beslan Mothers Committee, a prominent group at odds with the government, and other survivors and relatives of the dead.

On Thursday, Putin was in the southern region of Krasnodar, about 300 miles from Beslan, where he met students at an agricultural college.

"Today, a year on from the terrible tragedy in Beslan, millions of people in our country and abroad, all those who know about this terrible catastrophe, anyone who has a heart, are of course remembering that nightmare," Putin said in televised remarks. "Let us remember the children, those who perished, who suffered at the hands of terrorists."

Mourners in Beslan attend a ceremony marking the anniversary of the hostage tragedy at School No. 1, in which 331 people were killed, 186 of them children.