Russia on Saturday called on Kiev and insurgents in eastern Ukraine to give experts access to the crash site of Malaysia airlines fight MH17 to facilitate their investigation.

"The Russian side appeals to both sides of the Ukrainian conflict, urging them to do everything possible to enable access for international experts to the airplane crash area in order to take action necessary for the investigation," the Russian Foreign Ministry said in a statement.

Also on Saturday, Russian President Vladimir Putin and German Chancellor Angela Merkel agreed at a phone conversation that the MH17 crash in eastern Ukraine should be investigated by the International Civil Aviation Organization (ICAO) thoroughly and impartially.

The two leaders said bloodshed must be stopped immediately in eastern Ukraine, and that contact group talks involving representatives from conflict-hit regions should be resumed.

They also agreed that it "would be of fundamental importance" to implement Russia's initiative on the presence of Organization for Security and Cooperation in Europe (OSCE) monitors at two checkpoints on the Russian-Ukrainian border.

Some 30 OSCE observers arrived at the crash site on Friday to help supervise the handling of the remains of victims of the fatal crash.

A Malaysia Airlines Boeing 777 plane crashed Thursday in restive eastern Ukraine near the Russian border, killing all the 298 people on board.

The Ukrainian government and insurgents in the country's east have traded barbs, accusing each other of hindering the investigation and allowing bodies to rot.

Donetsk insurgent leader Aleksandr Borodai denied on Saturday that black boxes of the crashed Malaysian airliner had been found.

Borodai said they had not touched the site where the passenger plane crashed but they reserved the right to begin the process of taking away the bodies since the bodies would decompose in the heat.

"We ask the Russian Federation to help us with this problem and send their experts," Borodai, prime minister of the self-proclaimed Donetsk People's Republic, told a press conference.

Earlier in the day, Kiev accused insurgents of destroying evidence of international crimes from the wreckage of the Malaysian airliner.

"The terrorists have taken 38 bodies to the morgue in Donetsk," the Ukrainian government said in a statement.

Ukrainian Prime Minister Arseniy Yatsenyuk said insurgents in eastern Ukraine barred government experts from collecting evidence and threatened to detain them.

Malaysian Prime Minister Najib Razak said Malaysia should take possession of the black boxes from MH17.

Malaysian Transport Minister Liow Tiong Lai and Foreign Minister Anifah Anan left for Kiev on Saturday to help ensure that a team of Malaysian investigators is allowed access to the crash site.

Dutch Prime Minister Mark Rutte said his country, which lost 193 nationals in the crash, would not rest until the perpetrators of the possible attack on the crashed plane are detected, adding that his country have already sent its Safety Board to Ukraine to support an international investigation.

Meanwhile, Chinese President Xi Jinping and Premier Li Keqiang have extended condolences to Malaysia and the Netherlands over the loss of lives in the tragedy.

In a message of condolences to Malaysian Supreme Head of State Abdul Halim Mu'adzam Shah, Xi said he was shocked after learning about the crash.

"On behalf of the Chinese government and people, I express deep sympathy to your country over the unfortunate event and convey profound condolences to all the deceased including those from your country on board," Xi said.

In another message, Xi told Dutch King Willem-Alexander he was shocked to learn about the crash which killed a large number of Dutch passengers.

"We empathize with the Dutch government and people over grief. I, myself, and on behalf of the Chinese government and people, express deep sympathy to you and convey profound condolences to the deceased from your country," said Xi.

The Boeing 777-200, en route from Amsterdam to Kuala Lumpur, went down Thursday in eastern Ukraine, killing all 298 people aboard, including 193 Dutch passengers.