sentences:  These allied Chechens had reportedly asked for federal assistance and air support.According to the separatist account, the pro-Russian troops were ambushed by separatist fighters who inflicted heavy losses on them.On April 28, 2007, Russian officials asserted that at least three rebels were killed during a ground operation near the crash site, while Russian media reported five soldiers, including two Russian Ministry of Internal Affairs (MVD) servicemen, died in the fighting.