"The burden now is on Russia," Obama continued.
The President criticized Russia for violating Ukraine's sovereignty and said that if Russia continues to do so, consequences will worsen.
"The costs for Russia’s behavior will only continue to increase," he said.
Obama slammed the separatists for interfering with the investigation and removing evidence from the crash site.
“What exactly are they trying to hide?” he asked.
He also criticized the rebels for removing bodies from the site without the respect expected.
"This is an insult to those who have lost loved ones," Obama said.
He stressed that it has been four days since the plane was shot down and urged the separatists and Russia to begin cooperating immediately.
"Time is of the essence," he said. "The world deserves to know exactly what happened."