Three days of events are under way in Beslan to mourn the siege at a local school a year ago that left 331 people dead - 186 of them children.
Many were in tears as they entered the school's gym
Bells rang to mark the exact moment armed militants demanding an end to the Chechen war entered the building and took all those inside hostage.
Survivors and relatives of those who died laid wreaths and lit candles.
The siege ended when Russian forces stormed the school after explosions and gunfire were heard inside.
Police lined the streets of the small town in Russia's North Ossetia region and mourners had to go through metal detectors to reach School Number One.
To sombre music, thousands of people took flowers and lit candles in the charred crumbling shell of the gym, where more than 1,300 people were held captive for three days and where armed extremists strung bombs from the basketball hoops.
Loss and anger
The gym is now papered with photographs of those who died here - children, teachers and parents and those killed trying to save them.
A large red banner with white doves hangs on the walls of the school.
Many people in Beslan blame authorities for the bloodbath
"Everyone, all Ossetians will mark this mournful day, the saddest day maybe in our history," Sergei Zutsev - whose nephew was wounded in the siege - was quoted as saying by the Associated Press news agency.
"How could it be otherwise? They (the gunmen) shot children in the back - five-year-olds, 10-year-olds," Mr Zutsev said.
There were minor skirmishes at the scene, as some angry relatives of the victims tried to prevent the former director of the school from entering the schoolyard.
She was held hostage too, but some in Beslan accuse her of failing to protect their children.
The sense of loss here is as sharp as ever - but there is anger too, directed at the Russian authorities, the BBC's Sarah Rainsford in Beslan says.
People in the town are still looking for answers and talking of a cover-up, our correspondent says.
They want to know how so many gunmen made it to their school in the first place, and why officials refused to negotiate.
And most of all they want to know exactly who was responsible for the siege ending in a bloodbath.
"The government is supposed to guarantee our lives, take responsibility for our lives, and they haven't," said Susanna Dudiyeva, whose son was killed during the siege.
She earlier told reporters that President Vladimir Putin was unwelcome during the mourning ceremonies "since he is responsible for what happened in Beslan".
Mr Putin on Thursday led a minute's silence for Beslan victims in the southern city of Krasnodar.
Mrs Dudiyeva added that a group of victims' relatives would go to Moscow on Friday to air their grievances directly with the president.
And in an open letter, the Beslan Mothers' Committee and other relatives of the siege victims asked for asylum abroad.
"We have lost hope for an honest investigation... and we do not want to live any longer in a country where human life means nothing," the letter said.