Two female suicide bombers blew themselves up on Moscow's subway system as it was jam-packed with rush-hour passengers Monday, killing at least 35 people and wounding more than 30, the city's mayor and other officials said. Emergency Ministry spokeswoman Svetlana Chumikova said 23 people were killed at the Lubyanka station in central Moscow. The station is underneath the building that houses the main offices of the Federal Security Service, or FSB, the KGB's main successor agency. A second explosion hit the Park Kultury station about 45 minutes later. Chumikova said at least 12 were dead there, according to a report of the Associated Press. Moscow Mayor Yuri Luzhkov said both explosions were believed to have been set off by female suicide bombers as the trains entered the stations.