Senator John McCain, the 81-year-old Republican Party's 2008 US presidential nominee, has died, 13 months after revealing he was suffering brain cancer.
He died at his Arizona home on Saturday after stopping treatment on Friday for aggressive glioblastoma, which was diagnosed in July 2017.
McCain was known to the end as a pugnacious maverick, last month offering blistering criticism of US President Donald Trump's failure to stand up to Russian President Vladimir Putin.
"With the Senator when he passed were his wife Cindy and their family. At his death, he had served the United States of America faithfully for sixty years," his office said in a statement.
He had halted treatment Friday for aggressive glioblastoma, which was diagnosed in July 2017.
The retired Navy fighter pilot, who was shot down over North Vietnam in 1967 and held as a prisoner of war for more than five years, entered Congress in 1983 from Arizona and has served in the Senate since 1987.
Days after undergoing brain surgery in Arizona, with open stitches above his left brow, McCain appeared on the Senate floor in late July 2017, delivering a speech against partisanship and eventually casting the deciding vote against a major health care measure supported by Trump.
The hawkish chairman of the Senate Armed Services committee was a top Republican voice on defence and foreign policy.
He mounted losing presidential campaigns in 2000 and 2008.
McCain has been a leading Republican dissident since Trump took office in January 2017.
Last month, after Trump failed to publicly confront Putin about election meddling, McCain called the Helsinki summit "one of the most disgraceful performances by an American president in memory".
Trump says "deepest sympathies and respect" go out to the McCain family. death.
South Carolina Senator Lindsey Graham, a fellow military officer, tweeted that McCain was "one of my dearest friends and mentor."
"America and Freedom have lost one of her greatest champions," the Republican Graham wrote on Twitter.
Democratic National Committee chairman Tom Perez said that McCain "always will be an American hero."
"John McCain devoted his life to serving his country," Perez tweeted.
Paul Ryan, Republican speaker of the House of Representatives, said on Friday that McCain "personifies service to our country."
