Western powers on Monday ratcheted up the pressure on Moscow over the Malaysian plane disaster, as a train loaded with some 280 bodies was finally allowed to leave a rebel-held station four days after the jet crashed in strife-torn east Ukraine.
US President Barack Obama insisted that Moscow force pro-Russian insurgents controlling parts of east Ukraine to cooperate with an international probe into the disaster, and said chaos at the impact site was an "insult" to families of the victims.
With global fury mounting over the limited access given to investigators in the aftermath of the crash, the insurgents blamed for hampering the probe struck a breakthrough deal with Malaysia to hand over two black boxes recovered from the plane wreckage.
Read: Dutch Twitter avatars go black demanding MH17 bodies' return
Armed rebels forced emergency workers to hand over all 196 bodies recovered from the MH17 crash site and had them loaded onto refrigerated train cars bound for a rebel-held city, Ukrainian officials said. (AP photo)
Moscow, which has drawn ire for failing to rein in the pro-Russian rebels, meanwhile hit back at US accusations that it supplied the weapons allegedly used to shoot down the airliner.
On the ground, the animosity between Ukraine's warring sides was underlined by intense shelling which erupted in the rebel stronghold of Donetsk, a city just 60 kilometres (about 40 miles) from the station where the bodies had been held in refrigerated wagons.
Five people were killed and 12 wounded, as Ukraine President Petro Poroshenko said he was ordering his troops to hold fire within a 40-kilometre radius around the crash site, where forensic experts were heading.
Obama put the responsibility to set the situation straight squarely on Russia which has "direct influence over these separatists".
Russian President Vladimir Putin must prove "that he supports a full and fair investigation," Obama said, stressing "the burden now is on Russia to insist that the separatists stop tampering with evidence, grant investigators who are already on the ground immediate, full, and unimpeded access to the crash site."
Read: Train full of MH17 victims' bodies must leave: Dutch tell rebels
Putin had appeared to adopt a conciliatory tone Sunday, saying Moscow would do "everything in its power" to resolve the three-month-old Ukrainian conflict.
But on Monday, Moscow moved to slap down US accusations that the missile system used to shoot down the aircraft was transferred from Russia to separatists.
A senior Russian defence ministry official insisted that "Russia did not give the rebels Buk missile systems or any other kinds of weapons or military hardware".
Moscow challenged Kiev instead, saying records showed a Ukrainian military plane was flying just three to five kilometres from the Boeing 777 before it crashed on Thursday, killing all 298 people on board.
"With what aim was a military plane flying along a civilian aviation route practically at the same time and at the same flight level as a passenger liner?" asked Lieutenant-General Andrei Kartopolov.
Ukraine's President Petro Poroshenko swiftly dismissed that claim, calling it an "irresponsible and false statement" by Russia.
Read: Time for Russia to 'get out' of Ukraine, say Britain
Russia's riposte came after Kiev released fresh recordings of what it says are intercepted conversations between rebels conspiring to hide the flight's black boxes from international monitors.
And the US embassy confirmed as authentic recordings released earlier 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.
The Washington Post said Ukraine's counterintelligence chief had photographs and other evidence that three Buk M-1 anti-aircraft missile systems moved from rebel-held territory into Russia less than 12 hours after the crash.
And Poroshenko said the rebels were wasting their time as "it is simply impossible to remove and destroy all the evidence because the shrapnel is dispersed in the area of 20 square kilometres".
Ukrainian rescue workers collect bodies of victims at the site of the crash of the Malaysia Airlines Flight MH17 in Grabove, in rebel-held east Ukraine. (AFP photo)
Read: Rebels to give MH17 black boxes to Malaysia
Crash site chaos 'insult'
Earlier at the Torez railway station, Dutch investigators wearing masks and headlights were finally allowed to examine the remains of over 200 recovered bodies.
As they opened each of the train wagons holding the remains, an overpowering stench filled the air.
Patience was wearing thin over the limited access to the crash site in Grabove, but Malaysia's premier said late Monday rebels have now agreed to give investigators freedom to examine the scene.
Najib added that six members of his team would accompany the train carrying the victims' remains to the government-held east Ukrainian city of Kharkiv where they would be handed over to the Dutch, who have been asked by Kiev to lead the probe.
Earlier Monday, Obama denounced the chaotic removal of bodies by rebels as "an insult to those who have lost loved ones" while Australian Prime Minister Tony Abbott called it an "absolutely shambolic situation".
Read: Dutch anger swells at treatment of Ukraine bodies
As grief turned to anger, the public prosecutor's office in the Netherlands said it had opened a criminal probe into the downing of the plane, which had 193 Dutch on board.
The outrage was palpable in an open letter from Dutch national Hans de Borst, who lost his 17-year-old daughter Elsemiek.
"Thank you very much Mr Putin, separatist leaders or the Ukrainian government, for murdering my dear and only child," he wrote in the letter published by Dutch media.
"I hope that you're proud to have destroyed her young life and that you can look yourself in the mirror."
After meeting bereaved families, an emotional Dutch King Willem-Alexander said the disaster has left "a deep wound in our society".
Read: Putin must push separatists to aid MH17 probe, says Obama
Armed pro-Russian separatists stand guard at a crash site of Malaysia Airlines Flight MH17, near the village of Hrabove, Donetsk region. (Reuters photo)
The UN Security Council is expected to adopt an Australia-backed resolution demanding pro-Russian separatists grant unrestricted access to the crash site to international experts when it meets at 1900 GMT.
Canada announced new sanctions against Russia and European leaders have signalled they could do likewise as early as Tuesday -- barely a week after the last round of toughened embargoes.
Whole sectors of the economy including goods with possible military uses could be targeted, British Prime Minister David Cameron said.
The separatists' violent bid to join Russia 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.