Russian authorities are probing a terrorist attack on Moscow's busiest airport, where a suicide bomber set off a massive explosion that killed 35 people and injured at least 180 others on Monday.

The death toll from the carnage at Domodedovo Airport rose steadily in the hours after the blast, which occurred Monday afternoon in the international arrivals hall.

Airport spokesperson Yelena Galanova told Russia's NTV television that 35 people had died. Officials with Russia's Emergencies Ministry said 86 of the injured had to be hospitalized.

Within hours of the deadly explosion, Russian President Dmitry Medvedev told officials "from the preliminary information we have it was a terror attack."

The state-owned RIA Novosti news agency reported that authorities suspect a suicide bomber may have been responsible for the carnage. Other reports said the bomb had been packed with shrapnel, screws and ball bearings.

Mia Bloom, a fellow at Penn State University's International Center for the Study of Terrorism, said it is significant that the attack happened in the arrivals hall at the airport.

"If you think about how many security checks you go through on the way to your plane, think about how few security checks there are when you're leaving and you're picking up your luggage," Bloom told CTV News Channel in an interview from University Park, Pa., on Monday afternoon.

The Domodedovo attack may raise questions about whether "we need to change the way in which not only we start a flight, but also how we end a journey, in terms of security."

The attacks also casts doubt on Russia's ability to safely host the 2014 Winter Olympics in Sochi, as well as the 2018 World Cup.

Medvedev held an emergency meeting on Monday, as authorities planned how to proceed with their investigation into the Domodedovo attack. Security was immediately tightened at two other Moscow airports and other transportation facilities.

Medvedev also cancelled his Tuesday plans to travel to the World Economic Forum in Davos, Switzerland, where he was to promote Russia to foreign investors.

No one claimed responsibility for the blast at Domodedovo, but Chechen militants have previously been blamed for a number of terror attacks in Moscow. A double suicide bombing in the city's subway system last March killed 40 people.

While the violent battles that characterized Russia's two wars against Chechnya's separatists are long over, Islamic militants have continued a campaign of suicide bombings and other attacks. Much of the violence has been concentrated in Chechnya and other provinces in the Caucasus region, but others have targeted the Russian capital.

Canada's Foreign Affairs Minister, Lawrence Cannon, called the attack on Domodedovo a "cowardly act of terrorism." U.S. President Barack Obama also condemned the "outrageous" blast.

Russian Prime Minister Vladimir Putin directed the country's health minister to send staff to all hospitals treating the wounded to ensure they were getting the best care.

Powerful blast ‘shook' bystanders

Alexei Spiridonov was standing behind the desk of a car rental agency when the airport blast occurred around 4:30 p.m. about 100 metres from where he was standing.

"The explosion was so strong that it threw me against the wall," the 25-year-old Spiridonov explained in an interview with The Associated Press.

"People were panicking, rushing out of the hall or looking for their relatives. There were people just lying in blood."

Lufthansa official Yelena Zatserkovnaya was standing a similar distance from the blast.

"There was lots of blood, severed legs flying around," Zatserkovnaya said.

British Airways passenger Mark Green had just arrived at the airport when the explosion occurred.

"Literally, it shook you," Green said in an interview with BBC television. "As we were putting the bags in the car 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.

Fellow witness Sergei Lavochkin was waiting in the arrivals hall when he heard the explosion occur.

"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.

Passengers fled the arrivals hall in droves after the blast. A report from the RT television station indicated that authorities were moving passengers out of the terminal after the blast occurred.

The Domodedovo website indicates that is located 22 kilometres southeast of Moscow. It is considered the most up-to-date airport in the Russian capital.

Domodedovo has been targeted by suicide bombers in the past.

In 2004, a pair of suicide bombers bought illegal tickets from airport staff, boarded separate planes and blew themselves up while the planes were in the air. A total of 90 people died in the twin attacks.

With files from The Associated Press