Dutch experts on Tuesday prepared to fly out bodies recovered from downed Malaysian flight MH17, as Europe moved to punish Russia for fanning the rebellion in eastern Ukraine that it believes led to the crash.
The remains of victims were taken by train to the government-held Ukrainian city of Kharkiv five days after the jet was brought down, after rebels controlling the crash site finally released them and the plane's black boxes under intense international pressure.
But that was only the first leg of the long journey home for many of the 298 crash victims, with the bodies to be flown on Wednesday first to the Netherlands, which had 193 citizens aboard the doomed flight and is taking the lead in investigating the disaster.
Dutch experts said they were only sure 200 bodies had been delivered so far -- less than what the pro-Russian rebels had promised. International monitors also said some remains were left decomposing under the sweltering summer heat in the vast crash site in rebel-held east Ukraine.
The Netherlands has declared a national day of mourning on Wednesday, with Dutch royals and Prime Minister Mark Rutte due at the airport for the arrival of the bodies.
It will also be the start of a complex investigation and Rutte warned that the identification of the bodies alone could take months.
A truce has been declared by rival sides around the crash impact site, but just beyond, fighting raged on Tuesday as government troops pushed on with an offensive to wrest control of east Ukraine's industrial heartland from the pro-Moscow separatists.
Around 1,000 people have been killed in the 15-week conflict, almost a third of those victims of the plane crash that had brought Ukraine's war to the doorstep of countries as far away as Australia and Indonesia.
In Brussels, European foreign ministers agreed to speed up wider embargoes against Moscow, accused of arming the rebels who allegedly shot down MH17, with a new list of sanctions targets, including Russian individuals and entities, expected to be announced on Thursday.
Members of the media take pictures of black boxes belonging to Malaysia Airlines flight MH17, before their handover from Ukrainian pro-Russian separatist to Malaysian representatives, in Donetsk. Reuters
Read: Russia says MH17 probe should be done by 'international community', not Ukraine
'Human remains not picked up'
After intense international focus on what world leaders denounced as a "shambolic" situation at the crash site, rebels handed over two black boxes, which record cockpit activity and flight data, to Malaysian officials.
The rebels followed Kiev in announcing a ceasefire around the impact site in a move that should help international investigators examine the sprawling forensic minefield littered with poignant fragments from hundreds of destroyed lives.
"There were human remains that had not been picked up," said Michael Bociurkiw, a spokesman for European security body OSCE's mission to Ukraine after visiting the impact site.
"We did observe changes at the site. The fuselage has been moved. It appears that the cone section is split in two and it appears that the tail fin has been moved," he said.
Elsewhere in Ukraine's east, fighting was continuing with local authorities in the besieged cities of Donetsk and Lugansk reporting 10 civilians killed in 24 hours and Ukraine's military saying 13 soldiers had died.
As artillery fire rang out in Donetsk, a fighter, who declined to be named said: "They're firing on civilians! These are Ukrainians! They have become like wild animals."
Kiev reported on Tuesday that it had retaken Severodonetsk -- an industrial city of about 100,000 inhabitants around 120 kilometres from rebel stronghold Donetsk.
In a sign tensions are still running high a senior security official in Kiev claimed that Russia had massed over 40,000 soldiers along its border over the past week.
Watch: MH17 crash: Black Boxes of downed jetliner turned over
Putin vows to help
Russian President Vladimir Putin, who has borne the brunt of international fury, on Tuesday pledged to "do everything" to influence the separatists and ensure a full probe into the crash.
At the same time, he put the ball back in Kiev's court, saying that Ukrainian military offensive in the east was posing a danger to international investigators there.
"We are asked to exert influence on the militants of the south-east (of Ukraine). Of course we will do everything in our power.
"However this would be absolutely inadequate" given fresh attacks by Ukrainian troops, he said.
Moscow had earlier slapped down accusations that it had supplied the missile system allegedly used to attack MH17, with a senior defence official suggesting that Kiev may have been responsible for its downing.
Russia is already suffering the consequences of several rounds of sanctions imposed by the West, with the latest set unveiled less than a week ago.
The emerging giant is widely expected to sink into recession this year, hit by massive capital outflows over the Ukraine crisis.
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)
But more pain could still come as Britain is pushing for an arms embargo.
Britain's stance is however putting neighbour France in an awkward position, as Paris is keen to maintain its 1.2 billion euro ($1.6 billion) warship deal with Russia.
French Foreign Minister Laurent Fabius told the Britain to first put its house in order, pointing out that London was full of "Russian oligarchs".
Washington weighed into the debate, telling France pointedly that the delivery of Mistral-class warships to Russia would be "completely inappropriate" given the West's misgivings about Moscow's role in Ukraine.
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)
Black boxes 'intact'
Even as the investigation into the plane crash slowly begins, world leaders warned the rebels' handling of the crash site had already done much damage.
Australian Prime Minister Tony Abbott, whose country had 28 citizens and nine residents on the plane, said: "After the crime comes the cover-up. What we have seen is evidence tampering on an industrial scale. That has to stop."
Experts from Malaysia, reeling from their flagship carrier's second disaster in only four months after flight MH370 went missing in the Indian Ocean, were relieved that the black boxes were "intact with only minor damage."
Britain -- which lost 10 people in the crash -- agreed to decrypt the vital data from the recorders.