Sen. John McCain has been having a little fun over Twitter with Russian Prime Minister Vladimir Putin, goading the Russian into responding to his mocking tweets.

Earlier this month, McCain, R-Ariz., an avid Twitter user, tweeted: "Dear Vlad, The #ArabSpring is coming to a neighborhood near you," linking to a news article about the allegations of fraud after Russia's parliamentary elections.

Last Saturday, McCain tweeted, "#ArabSpring comes Moscow 'Russians rally vs Putin, election fraud,'" linking to a report on anti-government protests in Moscow.

Today, Putin responded, calling McCain, "nuts."

"He has a lot of blood of peaceful civilians on his hands. He must relish and can't live without the disgusting, repulsive scenes of the killing of Gadhafi," Putin said, referring to McCain's role as a pilot and prisoner of war in Vietnam, according to the Associated Press.

"Mr. McCain was captured in Vietnam and they kept him not just in prison, but in a pit for several years," Putin added. "Anyone [in his place] would go nuts."

McCain mocked Putin back, tweeting this morning, "Dear Vlad, is it something I said," and taking to the Senate floor to read, for the record, Putin's comments.

"Apparently, Mr. Putin was not amused," McCain said on the Senate floor, "I believe that he has been shaken, as he should have been, by the massive demonstrations that have taken place in Moscow and other cities in Russia."

Shortly after, Sen. Carl Levin, D-Mich., who serves on the Senate Armed Services Committee with McCain, came to his defense.

"I just wish we had a chance to straighten out Mr. Putin about Sen. McCain," Levin said on the Senate floor, "I don't think we'll have that opportunity, but maybe his own people will do that in a free election someday."