MOSCOW — The head of the Russian parliamentary commission investigating last year's Beslan school siege that left 331 dead said today that local law enforcement officials were negligent and ignored instructions to strengthen school security.

Alexander Torshin told the upper house of parliament that Russian Interior Minister Rashid Nurgaliyev and his deputy had sent telegrams less than two weeks before the militants' raid instructing the regional police department in North Ossetia, where Beslan is located, to beef up security on the first day of school.

But only a single policewoman was posted outside the Beslan school the day of the siege in September 2004, and she was taken hostage, he said.

Islamic militants seized Beslan's School No. 1 on the first day of school, taking more than 1,100 children, parents and staff hostage and herding them into the gymnasium, which they rigged with explosives.

The hostages suffered in hot, unsanitary conditions and were denied water by their captors during the ordeal, which ended in explosions and gunfire on the third day of the standoff. The dead hostages included 186 children.

The rebels, who were demanding that Russian troops withdraw from the nearby Chechnya region after a decade of separatist warfare there, had crossed heavily policed territory to reach Beslan, and victims' relatives are convinced they got help from corrupt officials.

Five senior policemen have been charged with criminal negligence for failing to prevent the raid.