Rescue workers have recovered flight recorders from the crash site of the Malaysian airliner shot down in eastern Ukraine but pro-Russian separatists are keeping hold of them.

On Sunday afternoon a video, reportedly recorded on Friday, was released by Ukraine's security services, showing rescue workers at the 25sq km crash site recovering what appeared to be a "black-box" flight recorder from the wreckage of MH17.

The footage was recorded in a wheat field in the village of Hrabove. Ukraine Emergency Ministry searchers found an orange-coloured flight-data recorder and handed it to a colleague.

Aleksander Borodai, a separatist leader, said on Sunday that his men were holding the instruments in Donetsk until experts could confirm they were the plane's flight recorders.

"They are being held and when they're identified by the International Civil Aviation Organisation we're ready to hand over those objects," Borodai said.

Access to flight recorders

Volodymyr Groysman, vice prime minister of Ukraine, said his government was not surprised that the rebels had access to the flight recorders.

"We were already suspecting that they had them [referring to the black boxes]. Over the last few days it has been hard to verify what has been happening with these black boxes," Groysman said.

The pro-Russian separatists also said they had loaded a train with more than 200 bodies recovered from the crash site.

News agencies said on Sunday no bodies remained at the site, a day after the Associated Press news agency reported rebels putting bagged bodies onto trucks and driving them away. No armed separatists were seen at the site.

Al Jazeera's Nazanine Moshiri, reporting from the site, said observers from the European security body, the OSCE, were present at a nearby railway station where the bodies were being stored in refrigerated carriages, but the monitors were not allowed to enter the carriages.

"We are waiting to hear where the train will be heading. We understand it will be going to Ukrainian government-controlled territory," she said.

Ukraine and the separatists accuse each other of firing a surface-to-air missile at the passenger jet as it flew from Amsterdam to Kuala Lumpur 33,000ft above eastern Ukraine on Thursday.

Both deny the charge. All of those on the plane - 283 passengers and 15 crew - were killed.

News reports of how the bodies had been decaying for days in the summer sun had ignited outrage worldwide, especially from the Netherlands, home to over half the victims.

Earlier, the Ukraine government claimed it had reached a preliminary deal with the separatists to remove the bodies.

The Dutch led the way in outrage over how the victims' bodies were being treated.

"The news we got today of the bodies being dragged around, of the site not being treated properly, has really created a shock in the Netherlands,'' Frans Timmermans, Dutch foreign minister, said.