MOSCOW – 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 38, the city's mayor and other officials said.

Emergency Ministry spokeswoman Svetlana Chumikova said 23 people were killed in an explosion shortly before 8 a.m. 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. The ministry later said 38 people were injured.

Moscow Mayor Yuri Luzhkov said both explosions were believed to have been set off on the trains.

"The first data that the FSB has given us is that there were two female suicide bombers," Luzhkov told reporters at the Park Kultury site.

The blasts practically paralyzed movement in the city center as emergency vehicles sped to the stations.

In the Park Kultury blast, the bomber was wearing a belt packed with plastic explosive and set it off as the train's doors opened, said Vladimir Markin, a spokesman for Russia's top investigative body. The woman has not been identified, he told reporters.

The last confirmed terrorist attack in Moscow was in August 2004, when a suicide bomber blew herself up outside a city subway station, killing 10 people.

Responsibility for that blast was claimed by Chechen rebels and suspicion in Monday's explosions is likely to focus on them and other separatist groups in the restive North Caucasus region.

In February, Chechen rebel leader Doku Umarov warned in an interview on a rebel-affiliated Website that "the zone of military operations will be extended to the territory of Russia , the war is coming to their cities."

Umarov also claimed his fighters were responsible for the November bombing of the Nevsky Express passenger train that killed 26 people en route from Moscow to St. Petersburg.

The Moscow subway system is one of the world's busiest, carrying around 7 million passengers on an average workday, and is a key element in running the sprawling and traffic-choked city.

Helicopters hovered over the Park Kultury station area, which is near the renowned Gorky Park.

Passengers, many of them in tears, streamed out of the station, one man exclaiming over and over "This is how we live!"

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