(CBS) — John McCain, the military hero who had a long career as a “maverick” Republican senator, has died, his Senate office confirmed on Saturday. He was 81.

In a statement, his Senate office said he died at 4:28 p.m. on August 25, surrounded by his wife Cindy and his family.

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McCain was diagnosed with glioblastoma, an aggressive form of brain cancer, in July 2017.

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On August 24, McCain’s family said that “with his usual strength of will,” he had chosen to discontinue treatment.

Though McCain had “surpassed expectations for his survival, … the progress of disease and the inexorable advance of age render their verdict,” the statement said.

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Friends and colleagues expressed their thoughts and condolences on social media following the news of McCain’s death.