At least 38 people have been killed and over 50 injured after two female suicide bombers blew themselves up on the Moscow metro on Monday morning.

Twenty five died in the first blast at 03:56 GMT as a train stood at the central Lubyanka station, beneath the offices of the FSB intelligence agency, the successor to the KGB. About 40 minutes later, a second explosion was detonated on a train at Park Kultury, leaving another 12 dead.

Yuri Luzhkov, the mayor of Moscow, told reporters the suicide bombers were believed to have set off their explosives as trains approached the Lubyanka and Park Kultury metro stations.

“The first data that the FSB has given us is that there were two female suicide bombers,” he told reporters at Park Kultury.

Damage to the stations themselves was minimal, and they were expected to reopen later today.

Yuri Syomin, the head of the Moscow prosecutor’s office, said the attacks had almost certainly been carried out by suicide bombers who boarded the metro at the height of the rush hour.

“Investigators are at the scene and people from bomb department are working there,” he said. “The figures are not final yet. Now is the time to save people.”

Moscow’s metro is one of the busiest subways in the world, carrying some 5.5m passengers a day.

Thirty nine people were killed in the last major attack on the Moscow Metro in February 2004. Six months later, a suicide bomber blew herself up outside a station, killing 10 people. Both attacks were blamed on Chechen rebels.

In November, the Caucasian Mujahadeen claimed responsibility for a bomb that killed 26 people on board an express train travelling from Moscow to Russia’s second city of St Petersburg.

Russian forces have scored a series of successes against militants in recent weeks. In February, at least 20 insurgents were reportedly killed in an operation by Russian security forces in Ingushetia.