VLADIKAVKAZ, North Ossetia -- Rescue teams on Monday searched forested foothills in southern Chechnya for signs of a missing army helicopter, while civilians protested a security sweep that has left two towns cordoned off for a week.

The crew of the Mi-24 helicopter gunship last contacted ground controllers from an area about 15 kilometers south of Grozny, said an official with the Moscow-appointed administration for Chechnya. Officials have so far failed to determine what happened to the helicopter.

Federal forces continued sweeps in the villages of Starye Atagi and Novye Atagi, detaining 45 people on suspicion of rebel links in the past 24 hours, the official said. About 200 residents, who were elsewhere when the raids began or who managed to break through the cordons, gathered in Grozny to call for an end to the abuse of civilians by servicemen.