Russian Prime Minister Vladimir Putin has branded US Senator John McCain "crazy" and claimed he has "blood on his hands".
He also criticised the U. S. for its handling of the death of Muammar Gaddafi.
Putin made the outburst at a live Q & A session streamed on Russia Today on Thursday.
He responded to comments by McCain that he would face an "Arab Spring" like that of Gaddafi on Twitter.
The PM said that McCain, who was a prisoner of war in Vietnam, had gone a bit "crazy" and was criticising Russia, not him personally.
"It's Russia he would like to be rid of. They are still afraid of our nuclear deterrent. We have our own foreign policy whether they like it or not. The West isn't uniform and we have more friends than enemies.
"I think [McCain] has the blood of innocent people on his hands," he added.
Putin claimed that Gaddafi's death "should have been democratic, but it wasn't".