Russia now says 14 of its officers have died in gunbattles with Islamic militants in Chechnya's capital.

The police force battled for more than 12 hours Thursday to kill 10 militants who had holed up in a high-rise and a school in Grozny, the Chechen capital.

The clashes dented the image of stability created by Chechnya's Kremlin-backed strongman after two separatist conflicts. The new violence raised fears of more attacks in Chechnya and widening unrest elsewhere in Russia's volatile North Caucasus region.

The Russian Interior Ministry updated its death toll from 10 to 14 on Friday. It was unclear whether some of the 28 officers who had been wounded had died.

The battles destroyed the school and the 10-story Press House.