Many Republican lawmakers, including Sen. John McCain, were caught off-guard by President Donald Trump's latest comments on Russia. | Getty McCain slams Trump for Putin comments on Senate floor

Sen. John McCain rebuked President Donald Trump on the Senate floor on Tuesday afternoon, lashing Trump's defense of Russian President Vladimir Putin over the weekend as "either terribly misinformed or incredibly biased."

The Arizona senator, who has emerged as one of Trump's chief Republican foils on foreign policy and national security issues, never mentioned Trump by name. But as he spoke in favor of anti-Putin activist Vladimir Kara-Murza, McCain clearly singled out Trump's comments about Putin on Sunday, when Trump compared Putin's strong-armed history of cracking down on dissidents to the United States' own record on human rights.


Kara-Murza "knew that there was no moral equivalence between the United States and Putin's Russia. I repeat, there is no moral equivalence between that butcher and thug and KGB colonel and the United States of America, the country that Ronald Reagan used to call a shining city on a hill," McCain said. "To allege some kind of moral equivalence between the two is either terribly misinformed or incredibly biased. Neither, neither can be accurate in anyway."

The public reprimand of a GOP president by a sitting Republican senator is rare, but many in the party were caught off-guard by Trump's latest comments on Putin, which he made in an interview with Fox News' Bill O'Reilly over the weekend. When O'Reilly noted that "Putin's a killer," Trump was quick to respond: “You got a lot of killers ... What, you think our country’s so innocent?”

Despite McCain's remarkable response to Trump on Tuesday, the GOP has yet to show it will take any concrete action to rein in the president. Republican senators are warning against the lifting of sanctions on Russia and threatened to vote against Secretary of State Rex Tillerson, but the former ExxonMobil CEO had the support of all Republican senators despite his close relationship with Putin.

Trump responded to the "haters" of his warmer relations with Putin on Tuesday morning.

"I don't know Putin, have no deals in Russia, and the haters are going crazy - yet Obama can make a deal with Iran, #1 in terror, no problem!" Trump tweeted.