President Medvedev blames security lapse for Moscow blast

There was no immediate claim of responsibility for yesterday's attack, but the action bore hallmarks of militants fighting for an Islamist state in the North Caucasus region on Russia's southern frontier.

"It's obviously a terrorist act that was planned well in advance in order to cause the deaths of as many people as possible," said President Dmitry Medvedev during a national broadcast.

"What happened shows that there were clear security violations," he said.

The attacker evaded security to carry the explosives into the airport's arrival hall.

North Caucasus rebels have threatened attacks against cities and economic targets in the run-up to parliamentary elections this year and 2012 presidential polls. The choice of Domodedovo, resulting in the deaths of several foreigners, suggested the attackers sought to raise uncertainty beyond Russia's borders.

Russia is due to host the 2014 Winter Olympics in Sochi, on the edge of the Caucasus, which some rebels consider part of the territory they aim to include in an Islamic state.

Medvedev, due to open the World Economic Forum today, delayed his departure to the Swiss city of Davos and was due to hold a meeting with his security services later today.

He vowed to track down and punish those behind the blast.

Russian media reports gave conflicting information about the identity of the suspected bomber, or whether there might have been more than one attacker.