President Trump Gives Speech for 9/11 Anniversary Remembrance Ceremony. (Video)

WASHINGTON — President Donald Trump observed the 16th anniversary of the 9/11 terror attacks Monday, his first presidential remembrance of the attack that killed nearly 3,000 Americans.

The president, joined by the First Lady, called the occasion "extraordinary."

"Our values will endure. Our people will thrive," Trump said, speaking at the Pentagon paying tribute to those who perished there on 9/11. "Our nation will prevail and the memory of our loved ones will never, ever die."

Trump, alongside Defense Secretary James Mattis and Joint Chiefs Chairman Gen. Joseph Dunford, spoke to America's strength in the face of hardship.

"The terrorists who attacked us thought they could incite fear and weaken our spirit but America cannot be intimidated," Trump said. "And those who try will soon join the long list of vanquished enemies who dared to test our mettle."

Prior to going to the Pentagon, the president and first lady stood stoically on the White House South Lawn, bowing their heads in honor of the moment that the first plane hit the North tower of New York's Twin Towers. White House staffers joined them on the lawn.

Vice President Mike Pence observed the solemn day in Shanksville, Pennsylvania, the site where United Airlines flight 93 crashed.

The 16th anniversary of the attacks that killed nearly 3,000 Americans comes as the nation weathers another week of devastating hurricanes ripping through the South. As the president held his silence, the rain and wind of Hurricane Irma continued to batter the state of Florida.

And that storm was clearly front of mind, with Trump sending prayers to those in the storm's path.

"When Americans are in need, Americans pull together,"he said, adding that "when we face hardship, we emerge closer, stronger, and more determined than ever."

Last year, Trump joined in a bipartisan 9/11 remembrance ceremony in New York City that later became a heated political moment in the 2016 presidential race. Former New York senator and then-Democratic presidential nominee Hillary Clinton appeared to stumble when she left the 15th annual remembrance in downtown Manhattan, a video that later made its way into Trump campaign ads and became fodder for Trump's attacks against his then-rival.