The black boxes that could help reveal the pattern of events before the downing of MH17 in eastern Ukraine will be examined by investigators in Britain, David Cameron says.
The flight data recorder and cockpit voice recorder, which were until yesterday being held by separatists near Donetsk, will be handed to the Air Accidents Investigation Branch (AAIB).
The Malaysian Prime Minister Najib Razak said the handover was part of an agreement he had reached with the rebel leader Alexander Borodai. Mr Najib said the black boxes appeared "to be in good condition".
From the cockpit voice recorder, the AAIB team in Farnborough, Hampshire, will be able to hear what the pilots were saying in the moments before the plane was apparently hit by a missile, killing 298 people. Although there would have been no time for the pilots to issue a Mayday warning, it is possible one of them saw something coming towards the aircraft.
The last two hours of a flight is recorded on the cockpit voice recorder while the other black box, the flight data recorder, provides a much longer record - several hours long - of how the plane's systems were operating and being operated.
The AAIB is said to house one of only two specialist "replay units" in Europe where it is possible to listen to the flight's audio log. The BBC reported that four speakers are used in a special room to create a "surround-sound effect".
Meanwhile, after a 17-hour train journey the bodies of the people killed in the Malaysia Airlines crash reached the Ukrainian government-controlled city of Kharkiv yesterday.
Dutch officials said 200 bodies had arrived in Kharkiv, not the 282 rebels had claimed had been on board the train. The remains will be flown to the Dutch city of Eindhoven where they are due to arrive today.
Authorities in the Netherlands have warned that formal identification could yet take "months". The crash site, in farmland held by the pro-Russian separatists, remained unsecured five days after the disaster.
And last night the White House said international investigators had been left unable fully to access the site. In Moscow, Vladimir Putin said Russia would do "everything in its power" to facilitate the investigation.
As the Ukrainian parliament voted to approve a decree from President Petro Poroshenko to call up more military reserves yesterday, scuffles broke out between nationalist politicians and those loyal to former President Viktor Yanukovych in the parliament building in Kiev.