A suicide bomber killed at least 35 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.
Aftermath of a suicide bombing at Moscow's busiest airport
President Dmitry Medvedev vowed to track down and punish those behind the bombing, which also injured about 130 people during the busy late afternoon.
Security has been beefed up at Moscow's other two airports, which will also receive diverted passengers who were flying toward Domodedovo, media reported.
"The explosion was right near me, I was not hit but I felt the shock wave -- people were falling," said Yekaterina Alexandrova, a translator who was waiting in the crowded arrivals area to meet a client flying in from abroad.
"Smoke started to gather -- there was a lot of smoke," she said by telephone. "Many of the injured went outside on their own, in a state of shock. Then they began to announce information about where to exit."
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 Domodedovo airport. The organisers will be tracked down and punished."
Russia's rouble-denominated stock market MICEX fell by nearly two percent 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.
Airport staff members were shown using flash lights to pick their way through the chaotic scene taped off immediately after the blast. Later videos showed emergency workers wheeling injured people out of the terminal on stretchers.
Prime Minister Vladimir Putin, who shares power in a 'tandem' arrangement with the less influential Medvedev, has staked his political reputation on quelling rebellion in the north Caucasus.
He launched a war in late 1999 in Chechnya to topple a secessionist government. That campaign achieved its immediate aim and helped him to the presidency months later; but since then insurgency has spread to neighbouring Ingushetia and Dagestan.
"It does not ... bode well for Russian ties to the North Caucasus and is yet another sign that what Putin started in 1999 by invading the rebellious republic of Chechnya has come home to roost again in the Russian capital," said Glen Howard, president of the U.S. Jamestown Foundation research institution.
"The bomb blast at Domodedevo will further strengthen the view among the Russian elite that Putin is losing control over security in the capital, which plays into the hands of his enemies."
Analysts say rebels are planning to increase violence in the run up to 2012 presidential elections that may well see Putin returning to the presidency.
Moscow suffered its worst attack in six years in March 2010 when two female suicide bombers from Dagestan set off explosives in the metro, killing 40 people.
Prime Minister Benjamin Netanyahu condemned the bombing and told Mevedev that Israel stood behind Russian efforts to fight terror.
U.S. President Barack Obama also condemned the attack and offered to extend any assistance to Moscow that it requires in connection with airport attack.
"I strongly condemn this outrageous act of terrorism against the Russian people," Obama said in a statement read by White House spokesman Robert Gibbs.
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