Malaysia Airlines Flight MH17 was shot down using a surface-to-air missile from an SA-11 anti-aircraft battery, killing all 298 people on board. The US intelligence community believes the separatists shot the plane down by accident.
"The Russian separatists we believe fired this, in general, could not be doing what they are doing without the Russians," State Department deputy spokesperson Marie Harf told reporters.
"And responsibility lays at the feet of President Putin, not just for this but for every incident that we have seen throughout this conflict" Harf said.
"We have laid out a very detailed case. We have been very open about our assessments here. The Russians have repeatedly lied about what is happening on the ground. They said there weren't troops in Crimea when there were troops all over Crimea. So there's just no credibility on their side," she said.
The White House said the question of who specifically fired the missile is for the investigation to determine.
"The fact that we don't know that yet does not absolve Russia of its responsibility for creating an environment in which militants were trained, given weapons, and encouraged to fight," said White House deputy press secretary Eric Schultz.
"We assessed that it was an SA-11 and that it came from a separatist-controlled area. And we know Russia has provided arming and training for these separatists," Schultz asserted.
He said the US is concerned by the Russian support for the separatists and hence taken a number of steps to rally around the international community in this regard.
"That is why I think President Putin feels increasingly isolated. That is why I think that people, even in Russia, are starting to question the direction President Putin is taking their country. I think that is why you see an international coalition building consensus around this," he said.
Pentagon spokesman Army Col Steve Warren said: "There is no question that the Russians are backing these separatists and they bear responsibility...For what happens in eastern Ukraine.
