At least 38 people have been killed after two female suicide bombers blew themselves up on Moscow Metro trains in the morning rush hour, officials say. 24 died in the first blast at the central Lubyanka station, beneath the offices of the FSB intelligence agency. About 40 minutes later, a second explosion ripped through a train at Park Kultury, leaving another 14 dead. The FSB said it was likely a group from the North Caucasus was responsible. Jessica Golloher reports from Moscow.