Dutch forensic investigators told armed separatists guarding train cars full of bodies from the downed Malaysia Airlines jet that the train must be allowed to leave as soon as possible Monday.
The experts from the Dutch National Forensic Investigations Team - which specialises in victim recovery and identification - also pressed for rebels to seal the refrigerated train cars parked in the rebel-held town of Torez.
Four days after Flight 17 was shot out of the sky, international investigators still have had only limited access to the crash site, hindered by the pro-Russia fighters who control the verdant territory in eastern Ukraine. Outrage over the delays and the possible tampering of evidence at the site was building worldwide, especially in the Netherlands, where 192 of the 298 victims were Dutch and another was Dutch-American.
AP journalists said the smell of decay was overwhelming at the Torez train station Monday and many with the inspectors wore masks or pressed cloths to their faces on the sunny, 84 degree Fahrenheit (29 degrees Celsius) day.
Earlier, a Ukrainian train engineer told The Associated Press that a power outage had hit the cars' refrigeration system for several hours overnight and it was not immediately clear why. The cooling system was back up early Monday, he said.
The investigators led by Peter Van Vilet of the Dutch LTFO forensic office stood for a moment with their heads bowed and hands clasped before climbing aboard to inspect the train cars, surrounded by armed rebels.
"I think the storage of the bodies is of good of quality," Van Vilet said. "We got the promise the train is going."
However, he said he did not know exactly when the train would leave. The Ukrainian government is hoping it will go to the government-controlled eastern city of Kharkiv, where it has set up a crash crisis center, but the rebels have not confirmed any movement yet.
In Kharkiv, another team of 23 international experts arrived, including 23 Dutch, two Germans, two Americans, one from the U.K. and three from the Australian Embassy.
At the charred crash site itself near the eastern village of Hrabove, emergency workers retrieved 21 more bodies Monday. Ukrainian Prime Minister Arseniy Yatsenyuk said 272 bodies have been recovered so far.
Fighting flared again Monday between the separatists and government troops in the eastern rebel-held city of Donetsk. City authorities said battles were taking place near the town's airport and warned residents to stay inside. An AP reporter heard several explosions and saw smoke rising from the direction of the airport.
Fighting began in mid-April between the government and the Russian-speaking separatists in eastern Ukraine after Russia annexed Ukraine's Crimean Peninsula a month earlier.
Pressure has been growing on Russian President Vladimir Putin, who the US and others say has backed and armed the rebels, to rein in the insurgents and allow a full-scale investigation into the downing of the plane. Russia has denied backing the separatists.
Australia, meanwhile, pressed for a U.N. resolution calling for uninhibited access to the rebel-controlled crash site and asking for the full cooperation of all countries in the region, including Russia.
In Britain, Prime Minister David Cameron said he hoped Russia will support the Security Council resolution.
"We would hope that, given what has happened, there would be unanimous support behind the principle of unfettered access to those who have the task of identifying and repatriating the victims, as well as to the investigators," Cameron's spokesman said.
The United States has presented what it called "powerful" evidence that the rebels shot down the Boeing 777 with a Russian surface-to-air missile. That evidence included video of a rocket launcher, one surface-to-air missile missing, leaving the likely launch site; imagery showing the firing; phone calls claiming credit for the strike and phone recordings said to reveal a cover-up at the crash site.
"A buildup of extraordinary circumstantial evidence ... it's powerful here," said US secretary of state John Kerry. "Russia is supporting these separatists. Russia is arming these separatists. Russia is training these separatists,"
Putin lashed out against the criticism Monday, accusing others of exploiting the downing of the plane for "mercenary objectives."
Putin said Russia was doing everything possible to allow a team of experts from the International Civil Aviation Organization, a U.N. agency, to investigate the scene. He again criticised Ukrainian government authorities in Kiev for reigniting the fighting with the rebels.
"If fighting in eastern Ukraine had not been renewed on June 28, this tragedy would not have happened," Putin said. "Nobody should or does have a right to use this tragedy for such mercenary objectives."
The head of counterintelligence for Ukraine's SBU security service, Vitaliy Najda, said the Buk missile launchers came from Russia and called on Russia to supply the names and ranks of the service personnel "who brought about the launch of the missile" so they could be questioned by investigators. He said the rebels could not have operated the sophisticated weapon without Russian help but did not provide specific evidence for his claim.
In Moscow, Russian officials offered evidence Monday to counter U.S. claims that the rebels were responsible for shooting down the jet. The Defense Ministry showed photos they said proved that Ukrainian surface-to-air systems were operating in the area in the days before the crash. The officials said the systems were operated nine times on Thursday, the day the plane was brought down.
Russian officials also said they had evidence that a Ukrainian Sukhoi Su-25 fighter jet had flown "between 3 to 5 kilometers (2 to 3 miles)" from the Malaysia Airlines jet.
"(The plane) is armed with air-to-air R-60 rockets, which can hit a target from a distance of up to 12 kilometers (7 miles) and guaranteed within 5 kilometers (3 miles)," said the chief of Russia's General staff, Andrei Kartopolov.
The defense ministry officials also insisted that Russia had not given the rebels any surface-to-air missiles.
Yatsenyuk, Ukraine's prime minister, angrily called on Russia to halt what he said was its support for the rebels.
"They have to stop, and President Putin has to realize, enough is enough," he said. "What we expect from Russia: To de-escalate the situation, to withdraw their agents, to close the border, to stop their support for these bastards, and to stick to international law and international observations."
In the Netherlands, Dutch Prime Minister Mark Rutte told a news conference that repatriating the bodies was his "No. 1 priority" and victims' families were being consoled by the Dutch royals.