The bill, which was approved earlier by both houses of Russia's parliament, authorizes the shooting down of hijacked planes if it appears possible that terrorists may intend to attack key facilities or populated areas.

The bill also allows the military to attack ships being used in a terrorist act. Shooting the planes or ships would be permitted even if hostages were on board.

The legislation is the latest legal measure to be passed in response to terrorist attacks in Russia in recent years. One of the most sweeping measures pushed by the Kremlin in the wake of the 2004 Beslan school hostage seizure radically changed how local legislative elections are held across the country.

Militants demanding that Russian troops withdraw from the nearby republic of Chechnyaseized the school in Beslan, and more than half of the 331 people killed were children. Most died in the climactic conclusion to the siege, when explosions tore through the school and security forces stormed the building.

The anti-terrorism law passed Monday also permits negotiations with terrorists who have taken hostages but bars consideration of their political demands, and calls for armed forces to use Russia-based weaponry against terrorists operating outside its borders.

The bill also permits law-enforcement officials to monitor telephone calls and take control of electronic communications in the area of a terrorist attack.