Pro-Moscow rebels have piled nearly 200 bodies from the downed Malaysia Airlines jet into four refrigerated boxcars in eastern Ukraine as cranes moved chunks of the Boeing 777, drawing condemnation from Western leaders over tampering with the crash site.

The United States, meanwhile, presented what it called "powerful" evidence that the rebels shot down the plane with a Russian surface-to-air missile and training.

Although other governments have stopped short of accusing Russia of actually causing the crash, the US blamed Moscow for the downing of Malaysia Airlines Flight MH17 last Thursday that killed all 298 people aboard.

"Russia is supporting these separatists. Russia is arming these separatists. Russia is training these separatists," US secretary of state John Kerry said.

Leaders of Britain, France, Germany and Australia spoke to Russian president Vladimir Putin by phone, urging him to use his influence on the separatists to ensure the victims could be repatriated and international investigators could have full access to collect evidence.

European foreign ministers will be meeting in Brussels tomorrow to consider further sanctions on Russia.

More than three days after the jet crashed, international investigators still have only limited access to the sprawling fields where it fell.

Meanwhile United Nations Security Council diplomats said the council would vote today on a draft resolution co-sponsored by Australia, France and Lithuania that would call for full access to the crash site and an independent investigation.

"Investigators must have immediate full access to MH17 crash site, & bodies treated with dignity," Britain's UN ambassador Sir Mark Lyall Grant tweeted.

Australian foreign minister Julie Bishop said she expected all 15 council members to back the proposal, which also asks for the full co-operation of all countries in the region, including Russia.

Russia has the power to veto the resolution as a permanent council member.

Australian prime minister Tony Abbott, whose country lost 28 citizens in the tragedy, said Mr Putin "said all the right things" during their conversation about ensuring an international investigation into the disaster.

"I'm now going to try to ensure that as far as Australia humanly can, we insist upon these things happening," Mr Abbott told Sydney Radio 2GB.

"The site is being treated more like a garden clean-up than a forensic investigation and this is completely unacceptable."

Russian officials have blamed Ukraine's government for creating the situation and atmosphere in which the plane was downed, but has yet to directly address claims that the separatists were responsible or were operating with technical assistance from Moscow.

The 42-square-mile crash site, spread out on farmland and villages, looked dramatically different yesterday, a day after armed rebels had stood guard while dozens of bodies lay in the summer heat.

The rebels were gone and 192 bodies were loaded into the refrigerated train cars in the rebel-held town of Torez, nine miles away.

The Ukrainian government said on its website that a second train with four refrigerator cars had arrived at Torez station.

Emergency workers, who the rebels have allowed to operate under their control, were searching the sprawling fields. Cranes moved pieces of the plane around, apparently to look for more bodies underneath.

By last night, Ukraine's emergency services agency said the total number of bodies found was 251, with dozens of body parts.

Mr Kerry expressed outrage at the "grotesque" behaviour of the rebels at the crash scene.

"Drunken separatists are stacking bodies into the back of trucks, removing materials from the site," he said. ''On Friday, we had 75 minutes of access to the site; on Saturday, three hours of access. This is an insult to everybody."

Dutch prime minister Mark Rutte, whose country lost 192 citizens, said repatriating the bodies was his "number one priority".

He said all efforts were aimed at getting the train with the bodies to "territory controlled by Ukraine", adding that a Dutch military plane was being sent to Kharkiv to set up a co-ordination centre.

Michael Bociurkiw, a spokesman for the Organisation for Security and Co-operation in Europe, said reports from the group's investigators in Ukraine suggested some bodies were incinerated without a trace.

Rebel leader Alexander Borodai denied the rebels were trying to tamper with evidence, saying the bodies and cockpit voice recorders, or "black boxes", would be turned over to a team of Malaysian experts he was expecting.

"The bodies will go nowhere until experts arrive," he said in the rebel-held city of Donetsk.

A group of investigators that included Malaysian officials was in Kiev, but said they would not go into rebel-held areas until they had better assurances about security.

The Ukrainian government, which has responsibility for the investigation, has also asked for help from the International Civil Aviation Organisation - a UN body - and Eurocontrol, a European air traffic safety organisation.

But it was clear that the rebels were interfering in the investigation.

Lyubov Kudryavets, a worker at the Torez mortuary, said that on the evening the plane went down, a resident brought in the bloodied body of a child aged about seven or eight. On Saturday, militiamen came to take away the body away, she said.

"They began to question me: 'Where are the fragments of rocket? Where are the fragments from the plane?'," Ms Kudryavets said. "But I didn't have any wreckage, I swear."

But experts say that even if investigators are granted access now, it might be too late.

"Even without any deliberate attempt at a cover-up, the crash site is already compromised in forensic terms," said Keir Giles, an associate fellow at the Chatham House think-tank.

In the Netherlands, church worshippers prayed for the victims as anger grew over the rebels' hindering of the investigation.

Silene Fredriksz-Hoogzand, whose son Bryce and his girlfriend Daisy Oehlers were among those killed, said she was appalled their bodies were not being handed over.

"Mr Putin, send my children home," she said, speaking on Sky TV from Amsterdam's Schiphol Airport. "Send them home. Please."