President Barack Obama called for Russia to make good on its claims of wanting an open investigation into the crash of the Malaysia Airlines flight in Ukraine last week.
"The burden now is on Russia to insist that the separatists stop tampering with the evidence, grant investigators who are already on the ground immediate, full and unimpeded access to the crash site," Obama said Monday.
Obama also threatened that the U.S. and the international community may further punish Russia if it does not cooperate.
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"My preference continues to be finding a diplomatic resolution within Ukraine—I believe that can still happen, that is my preference today and it will continue to be my preference," Obama said. "But if Russia continues to violate Ukraine's sovereignty and to back these separatists, and these separatists become more and more dangerous and now are risks not simply to the people inside of Ukraine, but the broader international community, then Russia will only further isolate itself from the international community and the costs for Russia's behavior will only continue to increase."
Finally, the president made a plea for the immediate recovery of the crash victims' bodies, saying that allowing the international community to access the remains is "the least that decency demands" from the separatists.
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Obama also took to the podium last Friday to address the downing of Malaysia Airlines Flight 17's crash in Ukraine.
In that speech he revealed that one American citizen, Quinn Lucas Schansman, had been among the nearly 300 killed in the wreckage. He also lay the blame squarely on Russia, although he indicated that the exact events leading up to the crash were still unknown.
"Time and again Russia has refused to take the concrete steps necessary to deescalate the situation," Obama said in the Friday speech. "I spoke to President Putin yesterday in the wake of additional sanctions that we'd imposed. He said he wasn't happy with them, and I told him that we have been very clear from the outset that we want Russia to take the path that would result in peace in Ukraine, but so far at least, Russia has failed to take that path."
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—By CNBC staff