Islamic militants launched a major attack on police and government buildings in a provincial capital in Russia's volatile Caucasus region Thursday, turning the city into a war zone wracked by gunfire and explosions. At least 49 people, including 25 militants, were killed. Chechen rebels claimed responsibility for the offensive in Nalchik, the capital of the republic of Kabardino-Balkariya, which opened a new front in Russia's decade-old war against Islamic rebels. President Vladimir Putin, beleaguered by attacks that have killed hundreds of civilians and underscored his failure to bring the turbulent Caucasus under control, ordered a total blockade of Nalchik to prevent militants from slipping out and ordered security forces to shoot any armed resisters. Twelve civilians, 12 police officers and 25 rebels were killed, said Fyodor Shcherbakov, a spokesman for presidential envoy Dmitry Kozak. He said the number was rising as bodies were being discovered. Deputy Interior Minister Alexander Chekalin told Putin that 50 militants had been killed and that 10 police officers had also died. Local officials said another three civilians were among the dead, and that 84 were wounded. Estimates of the number of militants involved ranged from 60 to 300, and Interfax quoted an aide to the president of Kabardino-Balkaria as saying late Thursday that 59 had been killed and 17 detained. The region has suffered a growing wave of violence apparently connected to Islamic extremists and the Chechen rebels' fight against Russian forces, which has devastated Chechnya and destabilized the entire Russian Caucasus since the early 1990s. Originally a separatist movement, the rebel struggle has melded increasingly with Islamic extremism and spread far beyond Chechnya's borders. Police and security forces have fought pitched battles with militants across the region, and the rebels have employed terrorist methods including suicide bombings and the seizure of more than 1,000 hostages last year in a school in the town of Beslan, about 100 kilometers (60 miles) southeast of Nalchik. The Kavkaz-Center Web site, seen as a voice for rebels loyal to Chechen warlord Shamil Basayev, said it had received a short message claiming responsibility for Thursday's attack on behalf of the Caucasus Front. It said the group is part of the Chechen rebel armed forces and includes Yarmuk, an alleged militant Islamic group based in Kabardino-Balkariya. The strategy of launching simultaneous attacks on police facilities was similar to last year's siege in another Caucasus republic, Ingushetia, in which 92 people died and police armories were looted. Basayev claimed responsibility for those attacks and the Beslan raid.