Moscow, 9 August 2000 (RFE/RL) - Russia's Federal Security Service says it has detained two men from the Caucasus region and is searching for a third suspect in connection with a bomb blast that killed seven people and injured more than 90 in central Moscow yesterday. Security Service deputy chief Vladimir Pronichev said one of the men being questioned is Chechen and the other is from Daghestan. No charges have been filed. No one has claimed responsibility for the explosion in the shop-lined pedestrian underpass near Pushkin Square. Moscow Mayor Yuri Luzhkov has linked the attack to Chechen separatists. But investigators say they are considering several possibilities. Chechen President Aslan Maskhadov has denied any separatist involvement. The Kremlin blamed Chechens for a series of bombings in Moscow and other cities last fall, but those cases remain unsolved.