MOSCOW -- A suicide bomber set off an explosion that ripped through Moscow's busiest airport on Monday, coating its international arrivals terminal in blood. The attack killed at least 31 people and wounded nearly 170, Russian officials said.
The terminal at Domodedovo Airport was engulfed by smoke and splattered with body parts after the mid-afternoon explosion that sprayed shrapnel, screws and ball bearings.
Amateur video posted on YouTube showed a pile of bodies on the floor, and other bodies scattered around. Luggage lay strewn across the ground and several small fires burned. A dazed man in a suit pushed a baggage cart through the carnage.
A man in blood-soaked clothes said he was just a few yards (meters) away from the explosion and thought he had been severely injured.
"The guy standing next to me was torn to pieces," said Artyom Zhilenkov, a 35-year-old driver. Doctors told him he had not sustained any injuries but he had been splattered by other victims' flesh and blood.
Investigative Committee spokesman Vladimir Markin said the bombing was most likely carried out by a suicide bomber and "attempts were being made to identify him." The Interfax news agency, citing law enforcement sources, said the head of the suspected bomber had been found.
President Dmitry Medvedev called it a terror attack and immediately ordered authorities to beef up security at Moscow's two other commercial airports and other key transport facilities. Medvedev postponed his own planned departure Tuesday for the World Economic Forum in Davos, Switzerland, where he was to give the opening address on Wednesday.
In Washington, President Barack Obama condemned the "outrageous act of terrorism" in Moscow and offered any assistance Russians investigators may want.
No one immediately claimed responsibility for the explosion, which occurred at 4:32 p.m. (1342GMT). Chechen militants have claimed responsibility for previous terror attacks in Moscow, including a double suicide bombing on the subway in March 2010 that killed 40 people and wounded more than 100.
Large-scale battles in Chechnya ended years ago, following two devastating wars between Russia and the republic's separatists, but Islamic militants have continued to carry out suicide bombings and other attacks. Most of the attacks have been in Chechnya and other predominantly Muslim provinces in the southern Caucasus region, but some have targeted Moscow, including its subways, buses and trains.
Monday's explosion is likely to renew security concerns as Russia prepares to hold major sports events including the 2014 Winter Olympics in Sochi and the 2018 World Cup.
Car rental agent Alexei Spiridonov, 25, was at his desk when the blast struck about 100 yards (meters) away.
"The explosion was so strong that it threw me against the wall," he told The Associated Press outside the airport. "People were panicking, rushing out of the hall or looking for their relatives. There were people just lying in blood."
Yelena Zatserkovnaya, a Lufthansa official, was a similar distance away. "There was lots of blood, severed legs flying around."
Airport workers used baggage trolleys to cart out the injured, she said.
Domodedovo Airport spokeswoman Yelena Galanova said 35 people were killed and scores were injured. The Emergencies Ministry, however, said 31 people were killed, 74 hospitalized with injuries and 94 were given medical treatment. The discrepancy could not immediately be explained.
Eurocontrol, the European air traffic control agency in Brussels, said Domodedovo was briefly closed to air traffic immediately after the blast, but soon reopened.
Sergei Lavochkin, who was waiting in the arrivals hall for a friend to arrive from Cuba, said passengers sprinted out of the terminal and emergency teams carried those unable to walk.
"I heard a loud bang, saw plastic panels falling down from the ceiling and heard people screaming. Then people started running away," Lavochkin told Rossiya 24 television.
Mark Green, a British Airways passenger who had just arrived, told BBC television he heard the huge explosion as he left the terminal.
"Literally, it shook you," he said. "A lot of alarms ... were going off and people started flowing out of the terminal, some of whom were covered in blood."
"One gentleman had a pair of jeans on that was ripped and his thigh from his groin to his knee was covered in blood," he added.
Green said thousands of people were in the terminal at the time of the blast.
Hours later, passengers arriving for their flights lined up outside waiting to pass through metal detectors that had been installed at all entrances. At least 20 ambulances and 10 fire trucks remained outside.
Built in 1964, Domodedovo is located 26 miles (42 kilometers) southeast of Moscow and is the largest of the three major airports that serve the Russian capital, handling over 22 million people last year. It is generally regarded as Moscow's most up-to-date airport, but its security procedures have been called into question.
In 2004, two suicide bombers were able to board planes at Domodedovo by buying tickets illegally from airport personnel. The female bombers blew themselves up in mid-air, killing all 90 people aboard the two flights.
Some 77 airlines now offer regular flights to Domodedovo, serving 241 international and national routes, according to airport's website.
The airport insists that security is one of its top priorities, claiming on its website that its "cutting-edge operations technology guarantees the safety of passengers' and guests' lives."
NATO Secretary-General Anders Fogh Rasmussen said he was "deeply disturbed" by the terror attack.
"I strongly condemn it," he said on Twitter. "NATO and Russia stand together in the fight against terrorism."
FIFA President Sepp Blatter was in St. Petersburg over the weekend to formally award Russia the 2018 World Cup. Prior to the signing, Prime Minister Vladimir Putin assured him that FIFA made the right choice.
AP writers Lynn Berry, Vladimir Isachenkov and David Nowak in Moscow and Raphael G. Satter in London contributed to this report.