(Alexei Druzhinin/AP)

McCain, the Arizona Republican and longtime critic of the Russian prime minister, has not been shy about his enthusiasm for the protests that have erupted in Russian cities since elections marred by allegations of ballot-stuffing and other irregularities.

“Dear Vlad, The ArabSpring is coming to a neighborhood near you,” McCain tweeted earlier this month. Two days later, he delivered remarks on the Senate floor excoriating the Russian government on missile defense, human rights and interference in Georgia, among other issues.

On Thursday, in his nationally televised and wide-ranging “phone in,” Putin was asked about McCain’s pugnacious tweet, and the suggestion that the kind of uprisings that have unfurled across the Middle East could be replicated in Russia.

According to reports from Moscow, Putin turned stone-faced.

“Mr. McCain was captured, and they kept him — not just in prison, but in a pit — for several years,” he said, referring to McCain’s years in captivity during the Vietnam War. “Anyone would go nuts.”

Putin also invoked the NATO mission in Libya, saying McCain has “the blood of peaceful civilians on his hands, and he can’t live without the kind of disgusting, repulsive scenes like the killing of Gaddafi.”

There is perhaps no love lost between McCain and Putin. On Thursday, McCain shot back on Twitter: “Dear Vlad, is it something I said?”

In Washington, McCain has been among the fiercest critics of the Russian prime minister, and of the Obama administration’s “reset” with Moscow. He is currently among the co-sponsors of legislation that would impose sanctions on Russian officials linked to human rights abuses.

At a Senate hearing on Wednesday, Obama administration officials echoed Clinton’s concerns about the elections in Russia but said they were encouraged that the Moscow government had permitted peaceful demonstrations this past weekend.

The administration hopes, Assistant Secretary of State Thomas Melia said, that such tolerance “becomes the new normal.”