Flake also said that he "admired" McCain's dramatic "no" vote on repealing the Affordable Care Act in July of previous year despite voting the other way, as well as McCain's emphasis on senators working together across party lines. He was 81 and had been battling brain cancer.
According to a statement from McCain's office, he died Saturday at 4:28 PM, adding.
Mr McCain's family said the late Vietnam War veteran, who was hailed as a hero for spending months in enemy prison after being captured, recently demanded that his doctors should stop administering medication because his cancer had reached irrecoverable stage. In the year since, John has surpassed expectations for his survival.
His family had previously said he had ended medical treatment for the condition, revealing that "the progress of disease and the inexorable advance of age render their verdict".
He had recently announced his decision to discontinue treatment.
Outside of his work, McCain was known for his love of the outdoors and commitment to his family.
From overseas, Canadian Prime Minister Justin Trudeau said McCain's "lifetime of public service" was "an inspiration to millions", while Israeli Prime Minister Benjamin Netanyahu praised him as "a great American patriot" whose "support for Israel never wavered". "Now, we're going to do what we can, get the best doctors we can find, and do the best we can".
As time went on, McCain's resistance grew more direct and his words sharper.
Former vice-president Joe Biden, who developed a friendship with McCain while they served together in the Senate, said the Arizona lawmaker will "cast a long shadow".
Sen. Lindsey Graham, a South Carolina Republican who's one of McCain's closest friends, said on Twitter that Cindy McCain "remains steadfast and is traveling every step of the way on this hard journey", and the "love provided by Meghan and the McCain children to their father has been comforting to witness". Biden's son Beau died in 2015 after fighting glioblastoma.More news: Twitch Prime Dropping Ad-Free Viewing, Game Discounts
In her own statement, Meghan praised her father for inspiring her. The dramatic move shocked his fellow Republicans, who thought repeal was a done deal. Unlike many other news organizations, we have not put up a paywall.
Even as McCain's health ebbed, he missed few opportunities to lash out at the president. "Even in times of political turmoil such as these, we share that awesome heritage and the responsibility to embrace it".
McCain had been a rare and outspoken Republican critic of Trump, accusing him of "naivete", "egotism" and of sympathizing with autocrats.
McCain found Putin's growing influence on the world stage particularly worrisome.
McCain's life was punctuated by wild highs and lows, from the horrific conditions he endured for almost 2,000 days as a prisoner of war to subsequent professional successes that brought him to the forefront of American politics.
McCain also frequently and directly criticized the commander in chief himself. He was the 2008 Republican presidential nominee in a contest he lost to President Barack Obama. McCain later said he regretted picking Palin.
The ticket failed to gain lasting traction in the face of an inspiring Obama campaign, especially following a financial crash in the fall of 2008 while George W. Bush was president. In 2000, McCain ran for president, but lost the nomination to George W. Bush.
News of Mr McCain's passing has elicited an outpouring of tribute and sympathy from Americans across the political aisle.
He attended 20 different schools on his way to graduating from a private boarding school in Virginia in 1954. He ejected from the plane, which knocked him unconscious and broke both his arms and a leg. On the ground he was beaten and stabbed with a bayonet by North Vietnamese soldiers. He was released in 1973. Others directly accused the deceased senator of pursuing his ideals at the cost of entire nations and wanting "to wipe Syria, Iran, Iraq, Palestine, and Vietnam off the map".
But it was McCain's fortitude after joining the Navy that would define him. He served in the Navy from 1958 until 1981, ending his career as a decorated captain with awards such as the Silver Star, Legion of Merit, Distinguished Flying Cross and Purple Heart.