An explosion ripped through the international section of Moscow's busiest airport, killing 35 people and wounding 168, officials said.
The massive blast, with an explosive force of seven kilograms of TNT, was caused by a suicide bomber, Russian officials said.
Sergei Lavochkin, was waiting in the arrivals hall for a friend to arrive from Cuba, when he heard the explosion.
He said he heard a massive bang, saw panels fall from the ceiling, then heard people screaming, and saw people running away.
British Airways passenger Mark Green had just arrived at the airport. He told BBC television that after the explosion he saw people streaming out of the terminal, some covered in blood. A British citizen and several other foreigners were among the dead, Russian news agencies reported
The LifeNews.ru website said many victims had metal fragments embedded in their bodies and that the explosive device was packed with bolts, nuts, nails and ball bearings.
The bomb appeared to have exploded in an area where people gather to meet travelers emerging from customs. The airport Domodedovo handles almost half the air traffic for Moscow. Served by 48 foreign airlines, it has flights to 243 cities around the world.
President Dmitry Medvedev, looking somber and downcast, told officials in a nationally televised briefing that it was a terrorist attack.
He ordered authorities to immediately tighten security at Moscow's two other commercial airports and other key transport facilities, including the subway system.
During the past 14 months, terrorists have targeted Moscow's transportation system with three bombings that have killed more than 100 people. In November 2009, a bomb derailed a high-speed, luxury train to St. Petersburg, killing 28. Last March, two suicide bombers from Dagestan set off bombs in two Moscow subway trains, killing 40. In both these attacks, Islamic radicals took responsibility.
In today's airport attack, Russian news wires report police are searching for three suspects from the North Caucasus. Investigative Committee spokesman Vladimir Markin says experts are trying to identify the suspected bomber.
Interfax reported police found the head of an Arab-looking man, aged between 30 to 35.
Leaders of the Islamist insurgency in the North Caucasus have vowed to bring the violence to the nation's capital. In Dagestan, Chechnya and Ingushetia, there are almost daily, armed attacks on government and police officials.
Domodedovo is generally regarded as Moscow's most modern airport, but its security procedures have failed in the past.
In 2004, two suicide bombers were able to board planes at Domodedovo by buying tickets illegally from airport personnel. The bombers blew themselves up in mid-air, killing 90 people aboard the two flights.
The blast represents a big setback for confidence in Russia's security as it gears up for two major international sporting events, the Winter Olympics in 2014 and the 2018 World Cup.
As President Medvedev postponed his visit to the World Economic Forum in Davos, international sympathy poured into Moscow.
White House spokesman Robert Gibbs said U.S. President Barack Obama called the bombing "an outrageous act of terrorism against the Russian people,"
NATO Secretary-General Anders Fogh Rasmussen said on Twitter he was "deeply disturbed" by the bombing and that "NATO and Russia stand together in the fight against terrorism."
German Chancellor Angela Merkel slammed the attack as"cowardly"
