He noted that the facts will be established during the investigation, "but if it turns out that this is the result of the actions of either separatists or Russia itself that mixed it (the civilian board of Malaysian Airlines - Ed.) with Ukrainian military aircraft, I think they will get the hell of reckoning," he said in the air of the American TV channel MSNBC.
He said that over the past few weeks, the world has learned "what the possibilities of Russia or pro-Russian separatists could be."
McCain published a statement calling for immediate military support of Ukraine on a personal Web page.
"It should be started immediately with the provision of weapons, including anti-tank and anti-aircraft weapons, which the Ukrainian leaders have repeatedly requested. It's a shame that the U.S. administration still refuses to help our Ukrainian partners with our military capabilities," McCain said.