A suicide bomber killed at least 31 people at Russia's biggest airport, Moscow-Domodedovo, on Monday in an attack that bore the hallmarks of militants fighting for an Islamist state in the north Caucasus region.
President Dmitry Medvedev vowed to track down and punish those behind the bombing, which also injured about 130 people during the busy late afternoon.
The Kremlin said Medvedev, who has called the insurgency in the north Caucasus the biggest threat to Russia's security, was delaying a trip to the Davos international business forum in Switzerland. The rebels have vowed to take the bombing campaign to the Russian heartland, hitting transport and economic targets.
"Security will be strengthened at large transport hubs," Medvedev wrote on Twitter. "We mourn the victims of the terrorist attack at the airport. The organisers will be tracked down and punished."
Russia's rouble-denominated stock market MICEX fell by nearly two per cent following the blast, which ripped through the arrivals hall. Twitter users posted mobile video phone footage of dozens of people lying on the floor as thick smoke filled the hall and a fire burned along one wall.
Russian security services had received warnings that an attack was planned at a Moscow airport.
"The special services had received information that an act of terror would be carried out at one of the Moscow airports," a security source. "Agents were seeking three suspects but they managed to access the territory of the airport, witness the explosion which their accomplice carried out and then leave the airport," the source said.
"A tip-off with a warning that something was being prepared appeared one week before the explosion," an airport security source told the Lifenews.ru website. "Even the place, by the customs, was named."