ROSTOV-ON-DON: Security forces and police killed six suspected militants, including two female suicide bombers, who had holed up in an apartment in southern Russia, the Federal Security Service said on Sunday. There were no casualties among the officers who conducted the special operation begun Saturday to liquidate the militants in Cherkessk, a city in Russia's southern Caucasus region, said Anna Lyzina, a security service spokeswoman in Cherkessk.Police and paramilitary troops have moved forcefully against suspected extremists in several cities of the region, which includes Chechnya, over the past year. Lyzina said that the four men and two women who were killed were subordinate to Chechen warlord Shamil Basayev and another alleged rebel, Achimez Gochiyayev, who was implicated in the series of 1999 apartment-house explosions that shook Moscow and other cities and became one of the Kremlin's arguments for launching a new war in Chechnya. Moldable plastic explosives, microchips and various explosive devices were found in the third-floor apartment where the militants were killed, she said. The Interfax news agency quoted an unnamed source in the regional Interior Ministry branch in Cherkessk as saying the militants had refused an order to surrender and had put up fierce resistance, so the decision was made to open fire on them with large-caliber machine-guns fixed to armored personnel car