TV screens show Prime Minister Vladimir Putin's annual phone-in session with Russians in Moscow.

An international war of words continues as Sen. John McCain responds to controversial comments from Russian Prime Minister Vladimir Putin. Thursday night at 6 p.m. ET on CNN’s “John King, USA.”

Story highlights

NEW: McCain criticized Russia's "back-sliding on human rights and democracy" last week

Vladimir Putin suggests U.S. drones and commandos had a role in Gadhafi's death

The Russian prime minister questions Sen. John McCain's soundness of mind

In response, McCain tweets: "Dear Vlad, is it something I said?"

Moscow CNN  — 

Russian Prime Minister Vladimir Putin accused U.S. drones and special forces of involvement in the death of Libyan leader Moammar Gadhafi in comments Thursday.

He also attacked U.S. Sen. John McCain over a warning that Russia might follow the same path as Libya, suggesting McCain was not of sound mind following his time as a prisoner during the Vietnam War.

Putin’s comments were prompted by a question during his traditional year-end question-and-answer program, broadcast live by state media.

Responding to a question about McCain purportedly predicting Putin would meet the same fate as Libya’s leader, the Russian prime minister described the televised images of Gadhafi’s final moments as “horrible, disgusting scenes” and pointed to U.S. involvement in his death.

“Is that democracy? Who did this? Drones, including those of the U.S., struck his motorcade and then commandos, who were not supposed to be there, called for the so-called opposition and militants by the radio, and he was killed without an investigation or trial,” Putin said.

U.S. Defense Secretary Leon Panetta acknowledged the day after Gadhafi’s death that “it was a U.S. drone combined with the other NATO planes that fired on the convoy” in which the Libyan leader was traveling outside the city of Sirte. But the Pentagon has denied that any U.S. forces were on the ground in a combat role in Libya.

When asked about McCain, Putin said he had met the senator from Arizona, but said the questioner’s description of him as the prime minister’s friend was “exaggerated.”

He then questioned the mental state of McCain, who ran for U.S. president in 2008, saying he “was taken prisoner in Vietnam, and was held not just in jail, but was put in a pit where he was kept for several years – any person under those circumstances would hardly remain mentally sane.”

Shortly afterward, McCain himself jumped into the row via Twitter, posting: “Dear Vlad, is it something I said?” and linking to a news story headlining the Russian prime minister calling McCain “nuts.”

The senator’s earlier Twitter posts had linked to news stories suggesting Russia might be in line for its own version of the “Arab Spring” but did not appear to suggest Putin would meet the same fate as Gadhafi.

Putin’s attack may be a response to critical comments made by McCain in the U.S. Senate last week.

McCain said his statement was a response to “the flawed Duma election that just occurred this weekend, and in light of my strong belief that the growing demand for dignity and uncorrupt governance that has defined the Arab world this year may impact Russia as well.”

McCain highlighted “the unfortunate issue of Russia’s continued back-sliding on human rights and democracy” and said the post-election protests were unsurprising given “the pattern of corruption and abuse that the Russian government has perpetrated over many years.”

He also criticized Russia’s “absolutely shameless” blocking of U.N. Security Council action on President Bashar al-Assad in Syria, despite widespread concerns over human rights abuses there.

“The demand for dignity, and justice, and democracy that is shaking the Arab world to its foundations will not be confined to that one region alone,” he said, but will spread and demonstrate that change is possible. “And it appears that message may be resonating with people in Russia,” he added.

In his televised remarks, Putin suggested that criticism of Russia was linked to its pursuit of “an independent foreign policy.”

While his country had more friends than enemies in Europe, he said, “some would like to sideline Russia so that it doesn’t get in the way of those wanting to dominate the globe.”

Putin’s latest comments come a week after he blamed the United States for encouraging opposition protests in the wake of Russia’s parliamentary elections.

He said U.S. Secretary of State Hillary Clinton had criticized the elections as “neither fair not free – even before receiving reports from international observers.”

This had sent a signal to opposition figures, Putin said, who “with the support of the U.S. State Department” then began “active work.”

Clinton responded to those remarks by restating her country’s “strong commitment to democracy and human rights.”

CNN’s Phil Black in Moscow and Laura Smith-Spark in London contributed to this report.