Sen. John McCain, R-Ariz., blasted President Trump for his comments during a joint press conference with Russian President Vladimir Putin Monday afternoon, and called it "one of the most disgraceful performances by an American president" in his lifetime.

McCain said in a statement that the summit with Putin was a "tragic mistake" that showed off Trump's "naivete" and "egotism." He also said Trump "proved" that he is unable to stand up to the Russian president.

[More: Nancy Pelosi: Trump was 'afraid' to mention Russian indictments to Putin]

“Today’s press conference in Helsinki was one of the most disgraceful performances by an American president in memory," McCain said. "The damage inflicted by President Trump’s naiveté, egotism, false equivalence, and sympathy for autocrats is difficult to calculate. But it is clear that the summit in Helsinki was a tragic mistake."

McCain and others were reacting to Trump's comment that both the U.S. and Russia were to blame for the current state of the relationship between the two sides. He also attacked the FBI when asked if he believes the U.S. intelligence community or Putin over claims about meddling in the 2016 election.

“President Trump proved not only unable, but unwilling to stand up to Putin," he said. "He and Putin seemed to be speaking from the same script as the president made a conscious choice to defend a tyrant against the fair questions of a free press, and to grant Putin an uncontested platform to spew propaganda and lies to the world."

McCain lit into Trump throughout his lengthy statement, saying that it is "tempting" to call the press conference a "pathetic rout," but said that Trump's moves were deliberate and calculated. He also said the comments were "a recent low point in the history of the American presidency."

“It is tempting to describe the press conference as a pathetic rout – as an illustration of the perils of under-preparation and inexperience. But these were not the errant tweets of a novice politician," McCain said. "These were the deliberate choices of a president who seems determined to realize his delusions of a warm relationship with Putin’s regime without any regard for the true nature of his rule, his violent disregard for the sovereignty of his neighbors, his complicity in the slaughter of the Syrian people, his violation of international treaties, and his assault on democratic institutions throughout the world."

“Coming close on the heels of President Trump’s bombastic and erratic conduct towards our closest friends and allies in Brussels and Britain, today’s press conference marks a recent low point in the history of the American Presidency," McCain said. "That the president was attended in Helsinki by a team of competent and patriotic advisers makes his blunders and capitulations all the more painful and inexplicable."

“No prior president has ever abased himself more abjectly before a tyrant. Not only did President Trump fail to speak the truth about an adversary; but speaking for America to the world, our president failed to defend all that makes us who we are — a republic of free people dedicated to the cause of liberty at home and abroad. American presidents must be the champions of that cause if it is to succeed," McCain concluded. "Americans are waiting and hoping for President Trump to embrace that sacred responsibility. One can only hope they are not waiting totally in vain.”

[Related: CNN's Anderson Cooper slams Trump's performance in front of Putin as 'disgraceful']