TOREZ, Ukraine — Rebels in eastern Ukraine took control Sunday of the bodies recovered from downed Malaysia Airlines Flight 17, and U.S. and European leaders demanded that Russian President Vladimir Putin make sure rebels give international investigators full access to the crash site.

U.S. Secretary of State John Kerry said Ukraine’s separatists were to blame for the downing of the aircraft, adding there was “extraordinary circumstantial evidence” that showed Russia was almost certainly complicit in arming the rebels.

“There’s a stacking up of evidence here, which Russia needs to help account for. We are not drawing the final conclusion here. But there is a lot that points at the need for Russia to be responsible,” Kerry said on NBC’s “Meet the Press” television show.

The key question of who controlled the collection of evidence at the sprawling crash site in rebel-held territory dominated the day’s rapid-fire developments. International monitors say armed rebels have limited their access to the crash site and Ukrainian officials said armed rebels took the bodies away from their workers by force.

Ukraine and the separatists accuse each other of firing a surface-to-air missile Thursday at Malaysia Airlines Flight 17 as it flew from Amsterdam to Kuala Lumpur some 33,000 feet (10,000 meters) above the battlefields of eastern Ukraine. Both deny shooting down the plane. All those onboard the flight — 283 passengers and 15 crew — were killed.

A wave of international outrage over how the bodies of the plane crash victims were being handled came amid fears that the armed rebels who control the crash site could be tampering with the evidence there.

Donetsk rebel leader Alexander Borodai said the bodies recovered from the crash site would remain in four refrigerated train cars in the rebel-held town of Torez, 15 kilometers (9 miles) from the crash site, until the arrival of an international aviation delegation.

“The bodies will go nowhere until experts arrive,” Borodai said, speaking in the rebel-held city of Donetsk.

He also said the plane’s black boxes have been recovered and will be handed over to the International Civil Aviation Organization.

Borodai said he was expecting a team of 12 Malaysian experts and that he was disappointed at how long they had taken to arrive. He insisted that rebels had not interfered with the crash investigation, despite reports to the contrary by international monitors and journalists at the crash site.

Ukrainian government officials, meanwhile, prepared a disaster crisis center in the government-held city of Kharkiv, expecting to receive the bodies, but those hopes appeared delayed or even dashed Sunday.

Deputy prime minister Volodymyr Groysman said 192 bodies and eight body parts were loaded onto the railway cars.

The leaders of France, Germany and Britain issued a statement demanding that Putin make sure that pro-Russia separatists in Ukraine give full access to investigators at the Malaysian plane crash site or risk the ire of Europe.

French President Francois Hollande, German Chancellor Angela Merkel and British Prime Minister David Cameron agreed Sunday to demand that Putin force separatists controlling the site to “finally allow rescuers and investigators to have free and total access to the zone.”

A statement from Hollande’s office said if Russia failed to immediately take the needed measures, EU foreign ministers may take action against Russia at a meeting Tuesday.

Ukraine says Russia has been sending sophisticated arms to the rebels, a charge that Moscow denies.

The U.S. embassy in Kiev issued a strong statement Sunday saying it has concluded “that Flight MH17 was likely downed by a SA-11 surface-to-air missile from separatist-controlled territory in eastern Ukraine.” It said over the weekend of July 12-13, “Russia sent a convoy of military equipment with up to 150 vehicles, including tanks, armored personnel carriers, artillery, and multiple rockets launchers” to the separatists. The statement also said Russia was training separatist fighters in southwest Russia, including on air defense systems.

The rebels have been strictly limiting the movements of international monitors and journalists at the crash site, which is near the Russian border.

Associated Press journalists saw reeking bodies baking in the summer heat Saturday, piled into body bags by the side of the road or still sprawled where they landed in the verdant farmland in eastern Ukraine after their plane was shot out of the sky.

By Sunday morning, AP journalists saw no bodies and no armed rebels at the crash site. Emergency workers were searching the sprawling fields only for body parts. Heavy machinery was seen moving plane debris around.

There was no immediate word on the bodies of the 102 other plane victims, but Michael Bociurkiw, a spokesman for monitors from the Organization for Security and Cooperation in Europe, said some bodies have likely been incinerated in the crash without a trace.

“We’re looking at the field where the engines have come down. This was the area which was exposed to the most intense heat. We do not see any bodies here. It appears that some have been vaporized,” he told reporters in Kiev on Sunday, speaking via phone from the crash site.

Alexander Pilyushny, an emergency worker combing the crash site for body parts Sunday, told the AP it took the rebels several hours Saturday to cart away the bodies. He said he and other workers had no choice but to hand them over.

“They are armed and we are not,” Pilyushny said.

Nataliya Khuruzhaya, a duty officer at the train station in Torez, said emergency workers loaded plane victims’ bodies Sunday into four sealed, refrigerated train cars.

Adding to growing claims that pro-Russian rebels have attempted to interfere with evidence, Ukraine’s security services released on Sunday purported intercepts of phone conversations between rebel militants discussing the location of the plane’s black boxes.

In one exchange, a man identified as the leader of the rebel Vostok Battalion, Alexander Khodakovsky states that two recording devices are being held by the head of intelligence of the insurgency’s military commander. The commander is then heard to order the militiaman to ensure no outsiders, including an international observation team near the crash site at the reported time of the call, get hold of any material.

The man identified as Khodakovsky says he is seeking information about the black boxes under instructions from “our high-placed friends … in Moscow.” The security service says all the recordings were made on Friday, but the authenticity of the recordings cannot be independently verified.

Vasily Khoma, deputy governor of the Kharkiv region where Ukraine has set up a crisis center to handle the disaster, said the Ukrainian state railway company had provided the refrigerated train cars. Kharkiv is 300 kilometers (185 miles) north of the crash site.

He said no information was available on when airplane parts would be brought to the city and that the priority now was on recovering bodies. He said a mobile lab to handle DNA analysis was being delivered.

In a blistering opinion piece for the Sunday Times, Cameron called the attack a “direct result of Russia destabilizing a sovereign state, violating its territorial integrity, backing thuggish militias and training and arming them.”

“We must turn this moment of outrage into a moment of action,” the British leader wrote.

In a coded rebuke of Merkel and other European leaders who have blocked efforts to impose tougher sanctions on Putin for Russia’s actions in Ukraine, Cameron said Europe must now “respond robustly.”

In the Netherlands, worshippers at church services across the country prayed Sunday for the victims of the Ukraine air disaster and their next of kin, as anger built over the rebels’ hindering of the investigation.

At the St. Vitus church in the central city of Hilversum, Father Julius Dresme summed up the nation’s pain.

“It’s terrible, and everybody’s hearts are bleeding and crying,” he said.