Hundreds of people are feared dead after a Malaysia Airlines passenger plane was shot down over eastern Ukraine.
Flight MH17 took off from Schipol airport in Amsterdam at lunchtime bound for Kuala Lumpur. There were 280 passengers and 15 crew on board.
Just over two hours later it was apparently shot down near the rebel-held village of Granobo, 25 miles from the Russian border.
Both the Ukraine government and the pro-Russia separatists fighting in the region denied responsibility.
As plumes of black smoke rose up near Grabovo, witnesses counted at least 22 bodies at the wreckage site.
The Boeing 777-200ER plane appeared to have broken up before impact and the burning wreckage - which included body parts and the belongings of passengers - was scattered over a wide area.
Ukrainian President Petro Poroshenko called the downing an act of terrorism and called for an international investigation into the crash. He insisted that his forces did not shoot down the plane. .
"We do not exclude that this plane was shot down, and we stress that the Armed Forces of Ukraine did not take action against any airborne targets," he said. "We are sure that those who are guilty in this tragedy will be held responsible."
US President Barack Obama called the crash a "terrible tragedy" and discussed the crash on the phone with Russian President Vladimir Putin.
The village of Grabovo is currently under the control of pro-Russia separatists and the area has seen severe fighting between the two sides in recent days.
Aviation authorities in several countries, including the FAA in the United States, had issued warnings not to fly over parts of Ukraine prior to today's crash. Within hours, several airlines, including Lufthansa and KLM, said they were avoiding parts of Ukrainian airspace.
Malaysia Airlines said Ukrainian aviation authorities told the company they had lost contact with Flight MH17 at 1415 GMT (1515 BST).
Anton Gerashenko, an adviser to Ukraine's interior minister, said on his Facebook page the plane was flying at an altitude of 10,000 metres (33,000 feet) when it was hit by a missile from a Buk launcher, which can fire up to an altitude of 22,000 metres (72,000 feet).
Igor Sutyagin, a research fellow in Russian studies at the Royal United Services Institute, said both Ukrainian and Russian forces have SA-17 missile systems - also known as Buk ground-to-air launcher systems.
A launcher similar to the Buk missile system was spotted earlier today near the eastern Ukrainian town of Snizhne, which is held by the rebels.
Separatist leader Andrei Purgin said he was certain that Ukrainian troops had shot the plane down, but gave no explanation or proof for his statement.
He said he did not know whether rebel forces owned Buk missile launchers, but said even if they did, they had no fighters capable of operating it.
Dutch Prime Minister Mark Rutte, who had been attending a European Union summit in Brussels, headed back to the Netherlands to deal with fall-out from the crash.
It was the second time that a Malaysia Airlines plane was lost in less than six months. Malaysia Airlines Flight 370 disappeared in March while en route from Kuala Lumpur to Beijing. It has not been found, but the search has been concentrated in the Indian Ocean far west of Australia.
Several planes have been shot down over eastern Ukraine in recent days.
Last night a Ukrainian fighter jet was shot down by an air-to-air missile from a Russian plane, Ukrainian authorities said adding to what Kiev says is mounting evidence that Moscow is directly supporting the separatist insurgents. Ukraine Security Council spokesman Andrei Lysenko said the pilot of the Sukhoi-25 jet hit by the air-to-air missile was forced to bail after his jet was shot down.
Russia's UN Ambassador Vitaly Churkin told reporters at UN headquarters in New York that Russia did not shoot down the Ukrainian fighter jet. "We didn't do it," he said
Pro-Russia rebels, meanwhile, claimed responsibility for strikes yesterday on two Ukrainian Sukhoi-25 jets.
The Ukrainian Defence Ministry said the second jet was hit by a portable surface-to-air missile, but added the pilot was unscathed and managed to land his plane safely
Moscow denies Western charges that it is supporting the separatists or sowing unrest in its neighbour.
Earlier this week, Ukraine said a military transport plane was shot down Monday over eastern Ukraine by a missile fired from Russian territory.
A leader of eastern Ukraine's pro-Russia rebels say they intend to call a three-day ceasefire to allow an investigation of the crash.
Rebel leader Alexander Borodai told the RIA-Novosti agency that discussions were under way with Ukrainian authorities on calling the short truce for humanitarian reasons.
He said international organisations would be allowed into the region.
Malaysia's prime minister said the jetliner did not make any distress call before it went down in Ukraine, and that the flight route was declared safe by the International Civil Aviation Organization.
Prime Minister Najib Razak said although Ukrainian authorities believe the Boeing 777 was shot down, he was unable to verify "the cause of this tragedy but we must, and we will, find out precisely what happened to this flight".
Mr Putin laid the blame for the crash on Ukraine.
A Kremlin statement said Mr Putin opened a meeting with his economic advisers by calling for a moment of silence over the crash.
Then, he said, "This tragedy would not have happened if there were peace on this land, if the military actions had not been renewed in south-east Ukraine. And, certainly, the state over whose territory this occurred bears responsibility for this awful tragedy."
United Nations secretary general Ban Ki-moon said "there is clearly a need for a full and transparent international investigation" into the crash.
He said the International Civil Aviation Organisation, a U.N. agency, was closely monitoring the disaster.