Sen. John McCain remembered by opponents and colleagues after decades in office

As Americans mourn the passing of U.S. Senator John McCain, his colleagues in public office across the country are issuing statements on the 81-year-old war hero, leader and politician who served the United States for 60 years.

As a Captain in the Navy, McCain's plane was shot down on a bombing mission over North Vietnam in 1967. He was severely injured and spent more than five years as a prisoner of war.

In a tweet posted on Saturday night, President Donald Trump wrote: "My deepest sympathies and respect go out to the family of Senator John McCain. Our hearts and prayers are with you!"

McCain ran as the Republican candidate in the 2008 presidential election, selecting former Governor of Alaska Sarah Palin as his running mate. McCain lost the race to then-Senator from Illinois Barack Obama.

Former President Obama paid tribute to the Arizona Senator, issuing a statement with his wife Michelle:

"John McCain and I were members of different generations, came from completely different backgrounds, and competed at the highest level of politics. But we shared, for all our differences, a fidelity to something higher - the ideals for which generations of Americans and immigrants alike have fought, marched, and sacrificed. We saw our political battles, even, as a privilege, something noble, an opportunity to serve as stewards of those high ideals at home, and to advance them around the world. We saw this country as a place where anything is possible - and citizenship as our patriotic obligation to ensure it forever remains that way.

"Few of us have been tested the way John once was, or required to show the kind of courage that he did. But all of us can aspire to the courage to put the greater good above our own. At John's best, he showed us what that means. And for that, we are all in his debt. Michelle and I send our most heartfelt condolences to Cindy and their family."

Former President George W. Bush released a statement, calling Sen. McCain, a "man of deep conviction and a patriot of the highest order."

Bush says in a statement that McCain was a "public servant in the finest traditions of our country" and is calling him a "friend whom I'll deeply miss."

Bush defeated McCain with his Republican presidential campaign in 2000. Bush later backed McCain's campaign in 2008.

While he never served as Commander in Chief, McCain was elected to the U.S. Senate from Arizona six times.

Arizona Gov. Doug Ducey has released a statement calling Sen. John McCain a "giant," an "icon" and an "American hero."

Ducey says McCain was an American who will never be forgotten, and he was proud to call him a fellow Arizonan. The Republican governor says McCain's "spirit, service and fierce independence shaped the state with which he became synonymous."

Ducey recalled that the senator always fought for what he thought was right, even when it wasn't popular. He says McCain's "dogged patriotism and passion for country," made him an inspiration.

The governor added that he hopes McCain's legacy will continue to inspire Americans to build a future that would make him proud.

The Associated Press contributed to this report.