President Donald Trump delivered remarks Tuesday in Shanksville, Pennsylvania, commemorating the 17th anniversary of the September 11, 2001, terror attacks.

Trump remembered the nearly 3,000 people killed in the attacks on the World Trade Center, the Pentagon and aboard Flight 93, which went down in Shanksville.

"We honor their sacrifice by pledging to never flinch in the face of evil and to do whatever it takes to keep America safe," Trump said.

WATCH: Soloist Delivers Stirring Rendition of National Anthem at Ground Zero

Trump saluted the nearly 5.5 million Americans who have enlisted in the Armed Forces since 9/11, and the nearly 7,000 service members who have died facing down the menace of radical Islamic terrorism.

He also thanked the 200,000-plus service members now serving overseas, and the citizens who protect our nation at home, including state, local and federal law enforcement.

"America's future is not written by our enemies. America's future is written by our heroes," Trump said.

He said the 40 passengers and crew on United Flight 93 embodied heroism when they fought back against the hijackers.

"As long as this monument stands, as long as this memorial endures, brave patriots will rise up in America's hours of need, and they too will fight back."

Watch the president's address above.

'A Slap in the Face': Benghazi Hero Slams Obama's 'Conspiracy Theories' Remark

Trump's Star Returns to Hollywood Walk of Fame After Being Smashed by Vandal

'I'll Write the Real Book!': Trump Blasts Woodward's Book, Calls It a 'Joke'