After announcing he would be ending treatment for aggressive brain cancer just one day ago, Senator John McCain has passed away at age 81.

McCain's office released a statement on Saturday afternoon, saying the GOP senator passed away at 4:28 p.m.

"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," the statement said.

Meghan McCain also released a statement on the passing of her father.

On August 24, the McCain family released a statement announcing that the politician would be ending his treatment after over a year.

The statement read:

Last year, Senator John McCain shared with Americans the news our family already knew: he had been diagnosed with an aggressive glioblastoma, and the prognosis was serious.In the year since, John has surpassed expectations for his survival.

But the progress of disease and the inexorable advance of age render their verdict. With his usual strength of will, he has chosen to discontinue medical treatment.

Our family is immensely grateful for the support and kindness of all his caregivers over the last year, and for the continuing outpouring of concern and affection from John's many friends and associates, and the many thousands of people who are keeping him in their prayers. God bless and thank you all.

Meghan wrote on Twitter that the "family is deeply appreciative of all the love and generosity" people have shown them over the past year. She added, "Thank you for all your continued support and prayers. We could not have made it this far without you - you've given us strength to carry on."

McCain was diagnosed with glioblastoma in July of 2017, when he said that the prognosis was "very, very serious."

"They said that it's very serious. That the prognosis is very, very serious," McCain told 60 Minutes. "Some say three percent, some say 14 percent. You know, it's a very poor prognosis. So I just said, 'I understand. Now we're gonna do what we can, get the best doctors we can find and do the best we can.' And, at the same time, celebrate with gratitude a life well lived."

The GOP senator would have turned 82 on August 29, and lived an incredible life. He survived being a prisoner of war for five and a half years in Vietnam. He wrote about his experience in may of 1973.

"I had a lot of time to think over there, and came to the conclusion that one of the most important things in life"”along with a man's family"”is to make some contribution to his country," McCain said.

McCain served in the Navy until 1981, and in 1982 he was elected into the U.S. House of Representatives from Arizona. Four years later, McCain was elected to the United States Senate. Since then, he won re-election five times.

President Donald Trump tweeted about McCain's passing.

McCain is survived by Cindy, his wife of 38 years, and his 5 children -- Meghan, John, James, Bridget and Sidney.

[H/T: TMZ]

Rest in peace, John McCain. Thank you for your service to this country.