MOSCOW - Russia's parliament drafted proposals for an anti-terrorism law on Monday, the day it began an inquiry into the Beslan school siege that killed more than 320 hostages, half of them children. Russia has tightened security after a spate of attacks which Chechen rebels say they carried out, including the Beslan tragedy, and has vowed pre-emptive strikes on "terrorist bases" anywhere.

"We believe it is necessary to prepare and adopt a federal anti-terrorism law, because existing legislation doesn't fully enable us to solve those tasks arising from the situation in the country," upper house speaker Sergei Mironov said after a meeting of the chamber. The Federation Council upper house called for a law that would deal out tougher punishments for people who collude with terrorists – by financing them or by helping them through professional negligence.

It also sought better definitions of terrorist threats and the varying degrees of danger they present and called for a full inventory of weapons used by security forces. The document, approved in principle, will be examined again next week. All legislation must be approved by the State Duma lower house and signed into law by President Vladimir Putin.

Last week, Putin announced a shake-up of the electoral system to boost Kremlin power, saying the changes were needed to beat terrorism. As well as suggesting the new law, members proposed amendments to existing legislation concerning security and law enforcement bodies.

The Federation Council also launched its inquiry into the Beslan school siege, sending representatives to the southern town to investigate how rebels were able to take hostage around 1,200 parents, teachers and children earlier this month. The chaotic end to the 53-hour siege prompted questions about the competence of the security services. Opinion polls showed people blamed corrupt police for failing to prevent the attack in the first place.

Analysts have doubted the value of an investigation carried out by a body that is unelected and has little power. The Duma, where elected deputies sit, plans to conduct its own probe.