Senate Armed Services Committee Chairman John McCain (R-AZ) fields questions from reporters on the resignation of National Security Adviser Michael Flynn and the Trump administrations connection to Russia, on Capitol Hill February 15, 2017 in Washington, DC. (Mark Wilson/Getty Images)

Senator John McCain (R-Ariz.) threatened to block Patrick Shanahan, President Donald Trump's nominee for Deputy of Defense Secretary, on Tuesday over his written statement that questioned the equipping of Ukraine with lethal weapons. Twitter reacted to the Senator's tense conversation by poking fun at his age and questioning his abilities as a senator.

McCain, 80, is the chairman of the Senate Armed Service Committee and was questioning Shanahan, a Boeing executive, who said he had to "look at" whether or not America should arm the Ukrainian government, a cause that the Arizona Senator has long advocated.

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During the committee hearing, Shanahan reversed his answer and firmly said that he would support arming the Ukrainians. "I support equipping the Ukrainians," he said.

Throughout the hearing, McCain made reference to the fact that Shanahan has been a part of a "major defense corporations of this country" — Boeing — but didn't mention the corporation. On Twitter, users seized on the omission as a sign of his deteriorating memory.

Other users called for his retirement.

McCain has been an advocate for arming the Ukrainian government since the Russian government annexed the Crimean peninsula following the overthrow of Ukrainian President Viktor Yanukovych in 2014.

"Have you not been aware of the issue?" McCain pressed. "Have you not aware of the actions of the Senate Armed Services Committee? Have you not been aware of the thousands of people who have been killed by Vladimir Putin? Have you missed all that in your duties at one of the major defense corporations in this country?" he continued.

McCain finished up his questions by chastising Shanahan for what he deemed an unsatisfactory answer to the question and threatened to block him from being considered for the Deputy of Defense Secretary position.

"Do not do that again Mr. Shanahan or I will not take your name up for a vote before this committee. Am I perfectly clear?" McCain said before yielding the floor.

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Earlier this month, McCain was criticized in similar terms on Twitter for his line of questions to former FBI Director James Comey during his hearing on June 8. In that hearing, he focused more on Comey's investigation into Hillary Clinton's email in a testimony about Donald Trump's campaign's involvement with the Russian government during the 2016 presidential election.

Following the criticism, McCain said that his confusing line of questions was the result of him staying up too late to watch the Arizona Diamondbacks' baseball game.

"I get the sense from Twitter that my line of questioning today went over people’s heads," McCain wrote in a statement. "Maybe going forward I shouldn’t stay up late watching the Diamondbacks night games."