"The expert analysis did not find mistakes in the actions of members of the crisis centre," said Deputy Prosecutor-General Nikolai Shepel.
He made the statement to a court in the southern Russian city of Vladikavkaz, where the trial of suspected hostage-taker Nur-Pashi Kulayev is being held.
Victims' relatives have demanded that top Russian officials testify at the trial and claim investigators are covering up for a bungled attack on the school which they say resulted in loss of life that could have been avoided.
According to the official version of events in early September 2004, a blast inside the school prompted an attack by Russian forces to free the hostages and 331 people were killed in the ensuing firefight, including 186 children and 31 hostage-takers.
"We believe the work of this committee was not objective.... The main aim was to cover up for top officials," Susanna Dudiyeva, head of the Beslan Mothers victim support group said.
President Vladimir Putin in September ordered prosecutors to open an inquiry into the hostage crisis after emotional protests by victims' mothers and criticism of Russian officers from the regional parliament.
Relatives have accused Russian officials of lying about the number of hostages who were held at the school, using incendiary bombs in their attack and taking too long to rescue hostages as the crisis ended in chaos.
The report presented by prosecutors on Tuesday was drawn up by a committee of experts who analysed the workings of a crisis centre that coordinated police, army and secret service during the siege between September 1 and 3 last year, Shepel said.
In the courtroom, relatives shouted at Mr Shepel, asking: "Who was in this expert committee?", and "Why didn't they let us know the results?"
An interim report from a separate parliamentary inquiry looking into the handling of the Beslan crisis by authorities was expected to be announced on Wednesday.
But the head of the inquiry, Deputy Federation Council Speaker Alexander Torshin, sought to play down expectations, saying "there will not be any sensations in the report."