A train carrying the remains of 280 people killed in the Malaysian plane disaster was finally allowed to leave a rebel-held region in eastern Ukraine as the militants declared a truce today around the crash site.

Five days after Malaysia Airlines flight MH17 was allegedly shot out of the sky, pro-Russian separatists conceded to a furious international clamour for the bodies and the plane's black boxes to be handed over to investigators.

The devices, which record cockpit activity and flight data, were handed to Malaysian officials by the prime minister of the self-proclaimed Donetsk People's Republic, Alexander Borodai, in front of scores of journalists.

"We will order a ceasefire in an area of 10 kilometres around" the site of the disaster, which killed all 298 people on board the plane, he said.

Meanwhile, after days of bitter wrangling, the rebels released the bodies of the dead. Loaded on a train, they will arrive in the government- controlled city of Kharkiv today before being put on a plane to the Netherlands, where the flight to Kuala Lumpur originated and which suffered the greatest loss, with 193 citizens killed in the crash.

The rebel concessions came after US President Barack Obama insisted that Moscow force the insurgents it is accused of backing to cooperate with an international probe into the disaster.