All sides have traded accusations as the investigation into the Malaysia Airlines crash gathered pace.

US intelligence authorities said a surface-to-air missile downed the plane, but have not yet been able to say who fired it.

Ukraine has called for an international probe to determine who attacked the plane and insisted it was not its military. Officials accused separatist rebels of shooting down the plane.

The rebels denied it and claimed government forces were behind the crash, which was denied by Ukrainian president Petro Poroshenko.

Russian president Vladimir Putin blamed Ukraine for the downing, saying Kiev was responsible for the unrest in its Russian-speaking eastern regions - but did not directly accuse Ukraine of shooting the plane down and did not address the key question of whether Moscow supplied the rebels with such a powerful missile.

Ukraine and the West have accused Russia of supporting the insurgents, a charge Moscow denies.

An angry Australian prime minister Tony Abbott demanded an independent inquiry into the downing, adding: "The initial response of the Russian ambassador was to blame Ukraine for this and I have to say that is deeply, deeply unsatisfactory.

"It's very important that we don't allow Russia to prevent an absolutely comprehensive investigation so that we can find out exactly what happened here.

"This is not an accident, it's a crime."

Australia lost at least 28 people in the disaster.

The crash site is spread out between two villages in eastern Ukraine with pro-Russia separatists apparently controlling access in and out.

Rebels who control the area said they had recovered most of the plane's black boxes and were considering what to do with them.

An assistant to the insurgency's military commander, Igor Girkin, said that eight out of the plane's 12 recording devices had been located at the crash site. Since planes normally have a flight data recorder and a cockpit voice recorder, it was not exactly which devices he was referring to.

He said Mr Girkin was still considering whether to give international crash investigators access to the crash site. Any investigators would need specific permission from the rebel leadership before they could safely film or take photos, he said.

Fighting apparently still continued nearby today, with the thud of missile launchers being heard.

One rebel militiaman in Rozsypne said the plane's fuselage showed signs of being struck by a projectile.

Anton Gerashenko, an adviser to Ukraine's interior minister, said on his Facebook page the plane was flying at about 33,000ft when it was hit by a missile from a Buk launcher, which can fire up to an altitude of 72,000ft. He said only that his information was based on "intelligence".

The area has seen heavy fighting between government troops and pro-Russia separatists, and rebels had bragged about shooting down two Ukrainian military jets in the region just a day earlier.

Ukrainian prime minister Arseniy Yatsenyuk described the downing as an "international crime" whose perpetrators would have to be punished in an international tribunal.

"Yesterday's terrible tragedy will change our lives. The Russians have done it now," he was cited as saying by the Interfax-Ukraine news agency.

Kenneth Quinn of the Flight Safety Foundation said an international coalition of countries should lead the investigation. The US has offered to help.

Malaysian transport minister Liow Tiong Lay insisted that the airline's path was an internationally approved route and denied accusations that Malaysia Airlines was trying to save fuel and money by taking a more direct flight path across Ukraine.

"I want to stress that this route is an approved path that is used by many airlines including 15 Asia-Pacific airlines. We have not been informed that the path cannot be used," he said

Malaysia's prime minister Najib Razak said there was no distress call before the plane went down.

Aviation authorities in several countries, including the FAA in the United States, had issued previous warnings not to fly over parts of Ukraine after Russia annexed the Crimean peninsula in March. Within hours of the crash, several airlines announced they were avoiding parts of Ukrainian airspace.