The city's mayor and other officials said that the female suicide bombers blew themselves up on Moscow's subway system, which was underneath the building where the main offices of the Federal Security Service, or FSB were located, killing atleast 37 people and leaving 38 injured.
Emergency Ministry spokeswoman Svetlana Chumikova said that aleast 23 people were killed in first explosion which took place shortly before 8 am at the Lubyanka station in central Moscow.
At least 12 were killed and 38 people were injured in the second explosion which occured at Park Kultury station, 45 minutes from first blast.
"The first data that the FSB has given us is that there were two female suicide bombers," Moscow Mayor Yuri Luzhkov told reporters at the Park Kultury site.
Luzhkov informed that both the twin explosions were believed to have been set off on the trains.
Vladimir Markin, a spokesman for Russia's top investigative body said that in the Park Kultury blast the attacker was wearing a belt packed with plastic explosive.
Markin said that the bomber triggered off the explosive just as the train's doors opened.
Chechen rebels have claimed responsibility for the blasts.