HRABOVE, Ukraine (AFP) — Pro-Russian militiamen in Ukraine loaded almost 200 bodies from downed flight MH17 into refrigerated train wagons yesterday as an outraged United States pointed the finger of blame directly at Moscow and demanded it ensure full access to the crash site for international investigators.

In what is the most unequivocal statement incriminating Russia, US Secretary of State John Kerry said the missile system used to shoot down the Malaysia Airlines jet was “transferred from Russia in the hands of separatists”.

European leaders warned Moscow of further sanctions over the crash while Kiev piled on the pressure by releasing fresh recordings of what it says are intercepted conversations between rebels organising to hide the flight’s black boxes from international monitors.

Malaysia Airlines flight MH17 was blown out of the sky last Thursday by what is believed to be a surface-to-air missile, killing 298 passengers and crew and dramatically raising the stakes in Ukraine’s bloody three-month conflict.

Insurgents said they had in hand material resembling black boxes, but promised to give them to “international investigators if they arrive”.

They were also holding the bodies in refrigerated train carriages until “the experts arrive”, said a rebel chief who explained that fighters had moved scores of bodies “out of respect for the families”.

“We couldn’t wait any longer because of the heat and also because there are many dogs and wild animals in the zone,” said Alexander Borodai, prime minister of the self-proclaimed Donetsk People’s Republic.

OSCE spokesman Michael Bociurkiw described the stench at Torez station, where armed separatists were guarding the grisly cargo of corpses, as “almost unbearable”.

The bodies, some dismembered and charred, had been left rotting in cornfields amid the mangled plane wreckage at the main crash site in Hrabove, with debris spread out for kilometres.

Ukrainian Deputy Prime Minister Voldoymyr Groysman said salvage crews found 27 more bodies and 20 body parts, with emergency workers in surgical masks seen carrying black body bags.

Fighting continued to rage between government forces and rebels in the east, with 13 people wounded in the last 24 hours just 100 kilometres (60 miles) from Hrabove.

And Ukrainian authorities said they could not guarantee the safety of investigators on the ground.

Kerry, whose government has condemned reported evidence-tampering and lax security at the crash site, said the missile system used to down the jet was supplied by Moscow.

“We know with confidence, that the Ukrainians did not have such a system anywhere near the vicinity at that point in time. So it obviously points a very clear finger at the separatists,” Kerry told CNN.

He also slammed as “grotesque” the manner in which “drunken separatist soldiers” were allegedly “unceremoniously piling bodies into trucks, removing both bodies, as well as evidence, from the site”.

Australia circulated a draft UN Security Council resolution demanding the rebels give “full and unfettered access” to the crash site, and for all parties to cooperate in the probe.

The suspicion of Russian intentions was also high, with Australian Prime Minister Tony Abbott telling ABC: “My fear is that Russia will say the right thing, but that on the ground interference with the site, interference with investigators, interference with the dignified treatment of bodies will continue.”

The leaders of France, Britain and Germany signalled they could ramp up sanctions against Russia as early as Tuesday — barely a week after the last round of toughened embargoes.