MOSCOW (AP) -- An explosion shook the busiest airport in the Russian capital on Monday afternoon and an aviation official said an unspecified number of people were killed.
There was no immediate word on the cause of the explosion in the international baggage-claim area at Domodedovo airport.
Russia's Investigative Committee said there were at least 20 casualties in the blast and the state news agency RIA Novosti quoted a spokesman for the Russian aviation agency, Sergei Izvolsky, as saying there were dead among the casualties.
You can follow live updates as the situation develops here.
Live video of the explosion that killed 35 people has been released. You can see it here.
China is also tightening security following Moscow's deadly blasts. The AP reports:
China's official Xinhua News Agency says security at Beijing's main airport has been tightened after the bombing in Moscow that killed 35 people.
Xinhua says patrols have been stepped up, more bomb-sniffing dogs deployed and greater attention focused on security camera surveillance at Beijing Capital International Airport.
MOSCOW — Russian Prime Minister Vladimir Putin vowed "retribution is inevitable" for the suicide bombing that killed 35 people at Russia's busiest airport, while President Dmitry Medvedev demanded robust checks at all transport hubs and lashed out at the airport for lax security.
Putin has built much of his reputation on harsh statements, but he did not elaborate on what kind of retribution he had planned or against whom in his comments Tuesday carried by Russian news agencies.
No claims of responsibility have been made for the attack Monday at Domodedovo Airport, which also left 180 people injured. Suspicion is likely to fall, however, on Islamist separatist insurgents from Chechnya or elsewhere in Russia's restive Caucasus region who have been battling Russian authority for over 15 years.
Chechen insurgents have claimed responsibility for an array of attacks in Moscow and elsewhere in Russia, including a double suicide bombing on the capital's subway system in March 2010 that killed 40 people. They also have hit Domodedovo Airport before, with two suicide bombers slipping through its security in 2004 to kill 90 people.
Clinton says the U.S. stands with the people of Russia in what she called "this moment of sorrow and grief."
Clinton spoke in Mexico, where she's attending diplomatic meetings.
Speaking to reporters after a meeting with Mexico's foreign minister, Clinton said Monday that the United States offers condolences and solidarity as Russia struggles to eliminate the threat of terrorism.
President Obama has strongly condemned the attacks. According to the AFP:
US President Barack Obama on Monday condemned as "outrageous" a suicide attack on a Moscow airport which left 35 people dead and dozens wounded.
"I strongly condemn this outrageous" act, the US leader said, quoted by White House spokesman Robert Gibbs.
"Any assistance that the government of Russia needs or wants, we certainly stand ready to help," Gibbs added.
According to Reuters, President Medvedev has postponed his trip to Davos due to the bombing. The president was slated to give the opening speech at the international conference.
Prime Minister Putin has spoken out on the attacks, focusing on mobilizing aid for the victims. According to the BBC he told Social Development Minister Tatyana Golikova:
It is necessary to prepare a draft government decree on providing financial aid to the families of those killed. I ask you and your deputies to go to the clinics, on the spot, to see how work is being organised to help the victims.
NATO Secretary General Anders Fogh Rasmussen has released this statement:
I am shocked by the terrorist attack at Moscow’s busiest airport. I strongly condemn this horrific act. I express my condolences to the families of those killed and injured and to the Russian people.
We are in this fight together. This is why in the NATO-Russia Council we have to strengthen our cooperation in the fight against terrorism.
This is a common threat that we have to face united. NATO expresses its solidarity with the Russian people and Government.
The BBC is reporting that aviation expert Chris Yates also believes this to be the work of a suicide bomber based on evidence at the scene. According to Yates:
Quite an amount of shrapnel has been found in the arrivals hall - ball bearings and other things that could be packed into a suicide belt. We could be talking about a walk-in suicide attacker walking in and blowing themselves up at that critical moment.
Pictures and video are beginning to emerge from the blast. More to follow as they become available.
Casualties are reported to have reached 35.
Flights are continuing to land at Domodedovo Airport as passengers desperately attempt to leave.
This is a terrorist attack according to the investigative committee, reports Russia Today. At least one suicide bomber is responsible for the blasts.
Comparions are being made on Russia Today with this attack and the Chechen suicide bombers who killed 39 people last March in the Russian metro. Similar to that attack, this would have been one of the busiest times in the airport in order to maximize casualties.
The Russian president is speaking now. He is saying that an investigation will be launched into the attacks.
The blast happened in the arrivals area, according to an eyewitness speaking on Russia Today.
Russian President Medvedev is reportedly planning an emergency meeting about the blast, Russia Today reports.
The Twitter hashtag for the Moscow airport explosion is #Domodedovo, the name of the airport. Several Russian Twitterers have said that Twitter broke the news first.
A Russian television station has shared a map of the airport and where the bomb exploded here.
Russia Today is reporting that the explosion had the power of 7 kg of TNT and that some eyewitnesses say there were two explosions.