Russian President Vladimir Putin has promised to cooperate with outraged world leaders seeking access to the site of downed flight MH17, after Washington squarely pointed the finger of blame at Moscow for the crash.
The under-fire Russian leader appeared to seek to temper international fury after 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".
The UN Security Council is on Monday due to consider a resolution demanding that pro-Russian separatists provide "unrestricted access" to the site in rural eastern Ukraine, as concerns rise over evidence tampering, the fate of victims' remains and black boxes.
In separate phonecalls, Putin promised Dutch Prime Minister Mark Rutte "full cooperation" in retrieving the bodies and black boxes, while Australia's premier Tony Abbott said the Russian leader had said "all the right things".
Both countries suffered heavy losses when Malaysia Airlines flight MH17 was blown out of the sky on Thursday by what is believed to have been a surface-to-air missile, killing 298 and dramatically raising the stakes in Ukraine's bloody three-month conflict.
The separatists' violent bid for independence is the latest chapter in a prolonged crisis sparked by Kiev's desire for closer ties with the EU -- a sentiment many in the Russian-speaking east do not share.
Evidence is mounting that the rebels downed the jet, pushing East-West ties already strained by the bitter tug-of-war over Ukraine's future to crisis point.
Kiev has released fresh recordings of what it says are intercepted conversations between rebels organising to hide the flight's black boxes from international monitors.
And the US embassy confirmed as authentic recordings released by Kiev of an intercepted call between an insurgent commander and a Russian intelligence officer as they realised they had shot down a passenger jet.
However, top Russian officials and state media have suggested that Kiev's new leaders staged the attack to blame the rebels.
Insurgents said they had in hand material resembling black boxes, but promised to give them to "international investigators if they arrive".
They on Sunday loaded nearly 200 bodies into 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".
Fighting has continued to rage between government forces and rebels in the east, and Ukrainian authorities said they could not guarantee the safety of investigators on the ground.
Putin has denied having any influence over the rebels, who have said they would only accede to Western demands over the crash if Kiev agrees to a truce.
However, in his third conversation with the Dutch prime minister since the crash, Putin promised he would help retrieve the bodies and black boxes.
"On both points Putin promised his full cooperation," a spokeswoman for the government press service RVD told AFP, asking not to be named.
Experts from the Netherlands -- in mourning after the loss of 193 nationals -- are set to arrive at the crash site on Monday.
Meanwhile, Australia's Abbot demanded Putin back his words with action after a phone conversation, however did not give details of what was discussed.
"He did say all the right things and now he has to be as good as his word," he told Macquarie Radio.
Australia proposed the resolution up for a vote at the UN on Monday, which Russia -- as a permanent member of the Security Council -- could veto.
The measure demands that armed groups controlling the area "refrain from any actions that may compromise the integrity of the crash site... and immediately provide safe, secure, full and unrestricted access to the site and surrounding area for the appropriate investigating authorities."
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.
This has piled pressure on Moscow, accused by Kerry of supplying the missile system used to down the jet.
"We know with confidence, 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".
Ukrainian Prime Minister Arseniy Yatsenyuk told a German newspaper that taking a plane down was an operation that would take professionals and not "drunken gorillas".
The Washington Post said Ukraine's counterintelligence chief had photographs and related evidence that three Buk M-1 anti-aircraft missile systems moved from rebel-held territory into Russia less than 12 hours after the crash.
Relatives wait around world
Ukrainian President Petro Poroshenko is pressing world leaders to recognise the militias as a terrorist organisation that should be put on trial at the Hague.
"We see no difference between the events in Ukraine and what happened on September 11 in the United States or the tragedy over Scotland's Lockerbie," Poroshenko said.
Relatives in the dozen countries whose citizens were killed pleaded for their loved ones to be brought home.
"At this current moment I hope the world can assist the families to bring back the remains," Zulkifli Abdul Rahman, brother-in-law of one of the cabin crew, told AFP in Kuala Lumpur.
The disaster has an added poignancy for Malaysia after the March disappearance of Malaysia Airlines flight MH370, carrying 239 passengers and crew.