Ukraine's government has accused pro-Russian rebels of taking 38 bodies from the scene of the disaster and destroying evidence.
"The government of Ukraine officially states that the terrorists, with the help of Russia, are trying to destroy evidence of international crimes," a government spokesman said in a Reuters report.
"According to government data, the terrorists have taken 38 bodies to the morgue in Donetsk," the statement added, accusing specialists with "strong Russian accents" of wanting to carry out their own autopsies.
Ukrainian authorities and Russian-backed separatists have accused each other of bringing down the plane with a surface-to-air missile.
Meanwhile other world leaders have called for calm in an already-heated international situation. China's President Xi Jinping has asked for a "fair and objective" investigation into the crash of the Malaysian Airlines plane.
"We feel consternation over the Malaysian plane that fell in Ukrainian territory and express our condolences to the victims and solidarity with their relatives," Xi added.
Malaysian Transport Minister Liow Tiong Lai is in the Ukraine capital of Kiev to help ensure an investigating team gets safe access to the site of the downed Malaysia Airlines Flight MH17.
However, Ukrainian and international observers have failed to agree on a security zone around the crash site adding to the confusion and efforts to secure evidence.
Defence Minister and former Transport Minister Hishammuddin Hussein, who was the chief spokesman for the Malaysian government during the crisis over the missing MH370 airliner in March, said the main priority was to ensure security and that any debris was not tampered with.
"We want to get to the bottom of this," he added, saying international cooperation was needed and that Malaysia had been in touch with officials in Russia, Ukraine, the United States, Britain and China.
"We do not have a position until the facts have been verified, whether the plane was really brought down, how it was brought down, who brought it down."