WASHINGTON (AP) — President Barack Obama is calling for international investigators to have “immediate and full access” to the site in eastern Ukraine where a passenger jet was shot down last week.

Obama accused pro-Russian separatists in the area of removing evidence and bodies from the crash site. He says that raises the question of “what exactly are they trying to hide?”

The president says the burden is on Russia and President Vladimir Putin to compel the separatists to cooperate with the investigation. Obama says that if Russia continues to violate Ukraine’s sovereignty, Moscow “will only further isolate itself” and the economic costs will continue to increase.

The White House says the missile that brought down the Malaysia Airlines plane was fired from an area controlled by the separatists.

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