Secretary of State John Kerry made the Sunday morning news show rounds to outline the United States' case—citing American and Ukrainian intelligence reports and social media that "obviously points a very clear finger at the [pro-Russian] separatists"—that Russia was responsible for the attack that brought down Malaysia Airlines Flight MH17, killing 298 people.

"This is the moment of truth for Russia," Kerry said on CNN's State of the Union. "Russia is supporting these separatists. Russia is arming these separatists. Russia is training these separatists, and Russia has not yet done the things necessary in order to try to bring them under control."

Appearing on CBS' Face the Nation, Kerry said that the U.S. has reason to believe that Russia has supplied the separatists fighting in Ukraine with the necessary weapons to shoot down the plane.

"What we have is a lot of evidence that points in the direction, that raises very, very serious questions, including the fact that a few weeks ago, we have 150-vehicle convoy coming from Russia, going into the east of Ukraine with tanks, artillery, multiple rocket launchers, armored personnel carriers, turned over to the separatists," Kerry said. More from CBS News:

Kerry also noted that there was an SA-11 surface-to-air missile in the vicinity of crash right before the plane was shot down, and said that there is documentation on social media that separatists bragged about shooting down the plane. The U.S. has also intercepted recordings of separatists talking to each other about the plane being shot down.

Finally, Kerry said, there is video evidence that a SA-11 system was moved back into Russia and is now missing from Eastern Ukraine. "So there's enormous amount of evidence, even more evidence than I just documented, that points to the involvement of Russia in providing these system, training the people on them," Kerry said.

"There's a buildup of extraordinary circumstantial evidence," Kerry said on NBC's Meet the Press. "We picked up the imagery of this launch. We know the trajectory. We know where it came from. We know the timing, and it was exactly at the time that this aircraft disappeared from the radar. We also know from voice identification that the separatists were bragging about shooting it down afterward." More from the Associated Press:

Shortly before Kerry's television appearances, the U.S. Embassy in Kiev, the Ukrainian capital, released a statement saying experts had authenticated the calls.

"Audio data provided to the press by the Ukrainian security service was evaluated by intelligence community analysts who confirmed these were authentic conversations between known separatist leaders, based on comparing the Ukraine-released internet audio to recordings of known separatists," the statement said.

British Prime Minister David Cameron, in a frontpage op-ed in the Sunday Times, appears to have expressed his solidarity in the case against Russia, writing, "If President (Vladimir) Putin does not change his approach to Ukraine, then Europe and the West must fundamentally change our approach to Russia." From the Guardian:

"If this is the case then we must be clear what it means: this is a direct result of Russia destabilising a sovereign state, violating its territorial integrity, backing thuggish militias and training and arming them," he wrote in the Sunday Times.

Cameron also appeared to criticise fellow members of the European Union for being slow to act against the Kremlin.

"For too long there has been a reluctance on the part of too many European countries to face up to the implications of what is happening in eastern Ukraine," he wrote.

"It is time to make our power, influence and resources count. Our economies are strong and growing in strength.

"And yet we sometimes behave as if we need Russia more than Russia needs us.

"We hope this is a wake-up call for some countries in Europe that have been reluctant to move," Kerry said on Face the Nation. "The way Russia is currently playing this dual-track policy, say one thing, do another, is really threatening both the larger interests as well as that region and threatening Ukraine itself."

[Image via AP]