Witnesses near the crash site where a Malaysia Airlines passenger plane came down in eastern Ukraine described a scene of chaos with dozens of bodies scattered around the smouldering wreckage.
Watch: Debris strewn crash site of Malaysian airline MH17 in Eastern Ukraine
An emergency services rescue worker said at least 100 bodies had so far been found at the scene near the village of Grabovo, and that debris from the wreckage was spread across an area some 15km in diameter.
Broken pieces of the wings were marked with blue and red paint - the same colours as the emblem of Malaysia Airlines, which said yesterday it had lost track of a Boeing 777 en route from Amsterdam to Kuala Lumpur that was carrying almost 300 people.
Watch: Families await news of Flight MH17
"I was working in the field on my tractor when I heard the sound of a plane and then a bang and shots. Then I saw the plane hit the ground and break in two. There was thick black smoke," said a witness, who gave his name only as Vladimir.
A separatist rebel from nearby Krasnyi Luch who gave his name only as Sergei said: "From my balcony I saw a plane begin to descend from a great height and then heard two explosions."
He denied the rebels had shot the plane down.
"This could happen only if it was a fighter jet or a surface-to-air missile [that shot it down]," Sergei said, adding that the rebels did not have weapons capable of shooting down a plane flying at such a height. The plane was flying at around 10,000 meters
Regional officials in Donetsk in eastern Ukraine confirmed the plane had come down near the town of Shaktarsk. Emergency services were rushing to the scene, a security source told Interfax-Ukraine. CNN reported that the black box had already been recovered by rescuers at the scene.
Ukraine Prime Minister Arseniy Yatsenyukcalled the downing of the flight from Amsterdam to Kuala Lumpur a "catastrophe"
The flag carrier, still reeling from the mysterious March 8 disappearance of flight MH370, said the aircraft was travelling from Amsterdam on an overnight flight to Kuala Lumpur with 280 passengers and 15 crew.
The incident is a fresh body blow to the carrier which, along with the Malaysian government, is still struggling to provide answers to the disappearance of flight MH370.
That plane went missing with 239 passengers and crew on board and is now believed to have diverted off its flight path and crashed in the remote Indian Ocean.
No trace of the plane has yet been found.
US President Barack Obama and Russian President Vladimir Putin yesterday discussed the plane crash during a phone call in which Obama warned Moscow of more sanctions if it does not change course in Ukraine.
"I can confirm that President Putin near the end of this morning's phone call with President Obama noted the early reports of a downed passenger jet near the Russia-Ukraine border," White House spokesman Josh Earnest said.
Earnest, briefing reporters on Obama's Air Force One flight from Washington to Delaware, said Obama was briefed by his advisers on the crash and directed top US officials to remain in close contact with Ukrainian officials.
"I can confirm that we've seen those reports but I'm not in a position to confirm any of the details at this point," Earnest said.
The Obama-Putin phone call was made at the request of Moscow a day after the United States and European countries imposed new sanctions on Russia.
Reuters, Agence France-Presse