An explosion rocked Moscow's busiest airport today in an apparent "terrorist attack", killing 35 and injuring dozens more, according to Russian officials.

The blast erupted in the arrivals area of the Domodedovo airport at 4:40 p.m. Moscow time. In addition to the 35 dead, another 130 were injured.

Initial reports published earlier today by Russia's state news agency RIA said witnesses had seen two suicide bombers carry out the attack. Later reports pointed to a single attacker. On Twitter, one purported eyewitness, Ilya Likhtenfeld, said the bomb was on a man standing in a crowd near a cafe.

Evgeny Khorishko of the Russian Embassy in Washington, D.C., told ABC News it was "too early to say" who may have been responsible.

"As you know there was an explosion in Domodedovo. Preliminary version is that it was a terrorist attack," Russian President Dmitry Medvedev told reporters. "People were killed and injured in that blast. I have just talked to the Healthcare Ministry and Emergency Ministry... We need to do all we can to make sure that victims get immediate medical help. Many ambulances are headed for Domodedovo and I would like to express my condolences to relatives of the victims."

U.S. President Barack Obama said he "strongly condemns this outrageous act of terrorism against the Russian people" and offered his condolences to those affected, according to a statement read today by White House press secretary Robert Gibbs. The U.S. State Department said it has no indication that any Americans were among those killed or injured.

Video taken inside the airport apparently minutes after the bombing shows the blast area full of smoke, with luggage scattered around the ground. Several bodies, prone and unmoving on the ground, are also visible.

Emergency services are on the scene and have evacuated several people from the blast zone, witnesses said according to The Moscow Times.

"All the injured r taken away. The bodies r not taken away," Likhtenfeld said on Twitter. "The investigation is going on. They r looking for the remnants of the suicide bomber."

Medvedev said a special investigative committee would be established to look into the incident and is currently meeting with law enforcement and the mayor of Moscow in response to the explosion, Khorishko said.