KIEV/BEIJING, July 22 -- Ukrainian rebels cleared the departure on Tuesday of a train loaded with remains of victims in crashed Malaysia Airlines MH 17 while handing over to Malaysian experts black boxes of the flight allegedly shot down in rebel-held eastern Ukraine.

The remains of the 298 victims, mostly Dutch, and the black boxes have become a part of conflict in crisis-plagued Ukraine because they could probably hold evidence telling who and what brought the Boeing 777 down on Thursday as it was flying from Amsterdam to Kuala Lumpur.

Under an agreement between Malaysian Prime Minister Najib Razak and Ukrainian insurgents, international forensics experts were finally allowed to access the crash site Monday and collect the bodies. Late on Monday, trucks arrived in Torez, a rebel-held town 15 km from the crash site, with about 200 plastic bags apparently filled with body parts and piles of luggage.

In Torez, the body bags were then loaded on a train heading for the government-ruled Kharkiv, where the remains would be taken

back to the Netherlands for identification, Dutch Prime Minister Mark Rutte said Monday.

Early on Tuesday, Donetsk insurgent leader Alexander Borodai, commander of the region where the incident occurred, handed over the two black boxes from MH17 to Malaysian investigators in Donetsk.

"Here they are, the black boxes," Borodai told journalists at the headquarters of the self-proclaimed Donetsk People's Republic as an armed rebel placed the orange-colored flight recorders on a desk.

Col. Mohamed Sakri of the Malaysian National Security Council said the two black boxes were "in good condition," adding that the top priority was to deliver the bodies of the victims to Amsterdam.

Borodai also said the insurgents would order a ceasefire in an area of 10 km around the site of the disaster.

The disastrous incident and the ensuing disruptions to the recovery of the bodies and black boxes have arounsed grave international concern in the international community, with the UN Security Council adopting a resolution on Monday, demanding safe and unrestricted access to the crash site as well as a "a full, thorough and independent international investigation into the incident in accordance with international civil aviation guidelines."

The 15 Council members also demanded that all military activities, including by armed groups, be "immediately ceased in the immediate area surrounding the crash site" to allow for security and safety of the international investigation.

They also demanded that "those responsible for this incident be held to account and that all states cooperate fully with efforts to establish accountability."

U.S. President Barack Obama on Monday also called for a full, unimpeded and transparent investigation into the crash of the Malaysian airliner.

"Our immediate focus is on recovering those who were lost, investigating exactly what happened, and putting forward the facts. We have to make sure that the truth is out and that accountability exists," he said in a statement.

In what has become a dramatic escalation in the worst East-West crisis since the Cold War, Obama once more pointed his finger at Russia, urging it to cut ties with the Ukrainian rebels.

"Now's the time for President (Vladimir) Putin and Russia to pivot way from the strategy that they've been taking and get serious about trying to resolve hostilities within Ukraine," Obama said.

The West has claimed that pro-independence insurgents in Ukraine's east shot down the airliner by a surface-to-air missile, threatening Russia with stiffer penalties for what they say is its backing of the insurgents.

British Prime Minister David Cameron said Monday that Europe must keep increasing pressure on Russia, warning that he would push the European Union to consider a new range of "hard-hitting" sanctions against Russia.

Vowing to do "everything in its power" to resolve the conflict in Ukraine, Moscow, however, challenged the Western allegations, demanding the United States make public its relevant satellite pictures.

Russia also questioned Ukraine over its deployment of Buk anti-aircraft systems not far from the crash site of the Malaysian passenger jet.

"For what purpose and against whom were these missile systems deployed? As is known, the (anti-government) militia has no aviation," Andrei Kartopolov, chief of the main operative department of the General Staff, told a news briefing, pointing to a photo of what he said was a Buk system detected 8 km south of Shakhtarsk, where the plane crashed.

He added that Russia had not handed Buk systems or other kinds of weapons or military hardware to the pro-independence militants in Ukraine.

Meanwhile, Russia's air traffic control records have shown that a Ukrainian Su-25 fighter jet was flying close to the passenger plane before the crash, he said.

China on Tuesday called on all parties involved to cooperate with the international investigation into the crash of the plane.

"China supports an independent, fair and objective international investigation into the crash of the Malaysia Airlines flight," Foreign Ministry spokesman Hong Lei said.

"The International Civil Aviation Organization should be allowed to play its full role in the investigation," the spokesman added.