Russian leaders have vowed to avenge today's double rush-hour suicide bombings on packed metro trains in Moscow that killed dozens.

Prime Minister Vladimir Putin vowed those behind the attacks would be 'destroyed'.

Russian President Dmitry Medvedev later visited the Lubyanka metro station to lay a wreath of red roses on the platform.

He vowed 'we will find and wipe out' those behind the blasts, calling them 'wild beasts'.

At least 38 people were killed and 64 wounded after suicide bombers detonated explosives on two Moscow metro trains during the morning rush hour.

The first blast, just before 8am (5am Irish time), exploded on the second carriage of a train as it stood at the Lubyanka metro station. It killed at least 24 people.

Lubyanka station is close to the headquarters of Russia's main domestic security service FSB.

Another blast about 40 minutes later went off on the second carriage of a train waiting at the Park Kultury metro station, killing 14.

Officials say the death toll could rise as many of the survivors sustained serious injuries.

'Two female terrorist suicide bombers carried out these bombings,' Moscow Mayor Yuri Luzhkov told reporters at Park Kultury metro station.

FSB chief Alexander Bortnikov said the bombs were filled with bolts and iron rods. Russian prosecutors have begun an investigation.

No group immediately claimed responsibility for the blasts, but the authorities blamed militants from the north Caucasus.

Mr Bortnikov said: 'The preliminary theory is that the terrorist attacks were carried out by terror groups linked to the north Caucasus. We consider this the main theory.'

Mr Medvedev said Russia would fight terror without hesitation and to the end. He ordered security to be stepped-up on transport across the country.

Mr Putin, who has broken off a trip to Siberia, said: 'A crime that is terrible in its consequences and heinous in its manner has been committed.

'I am confident that law enforcement bodies will spare no effort to track down and punish the criminals. Terrorists will be destroyed.'

Russian news agencies said body parts thought to come from the two women have been recovered at the two stations and sent away for analysis.

Both stations have since re-opened for the evening rush hour.

The current death toll makes it the worst attack on Moscow since February 2004, when a suicide bombing killed 39 people and wounded more than 100 on a metro train.

US President Barack Obama and European Union leaders have condemned the bombings.

Mr Obama said: 'The American people stand united with the people of Russia in opposition to violent extremism and heinous terrorist attacks that demonstrate such disregard for human life, and we condemn these outrageous acts.'

Governments and nations the world over ‘face a common enemy’ in terrorism, US Secretary of State Hillary Clinton said.

A spokesman for British Prime Minister Gordon Brown said he was 'appalled' by the scenes in Moscow and that 'there can never be any justification for acts of this kind'.

Minister for Foreign Affairs Micheál Martin has said he is 'horrified at the appalling loss of live' in the bombings.

'I condemn those responsible for this gratuitous act of terrorism on innocent people on their way to work.

'Nothing can justify such an outrageous attack, which has taken the lives of so many and left scores injured.

'On behalf of the Government and people of Ireland, I send heartfelt sympathy to the bereaved and offer my best wishes for a swift recovery to the injured.'