Story highlights Trump observed the 16th anniversary of the September 11 terrorist attacks

"On that day, not only did the world change but we all changed," Trump said

(CNN) President Donald Trump observed the 16th anniversary of the September 11, 2001, terrorist attacks in ceremonies Monday at the Pentagon, promising that the United States will "prevail" and that the memory of those lost will "never, ever die."

"On that day, not only did the world change but we all changed," Trump said at the National 9/11 Pentagon Memorial.

"Our eyes were opened to the depths of the evil we face but in that hour of darkness we also came together with renewed purpose. Our differences never looked so small. Our common bonds never felt so strong," he added.

In the 2001 attack orchestrated by al Qaeda leader Osama bin Laden, 19 men hijacked four fuel-loaded US commercial airplanes bound for West Coast destinations. A total of 2,977 people were killed in New York City, Washington, DC, and outside of Shanksville, Pennsylvania.

Earlier Monday morning, Trump observed a moment of silence on the White House South Lawn to mark the moment the first plane hit the World Trade Center. Former President Barack Obama held the same ceremonies while in office.

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