In a somber ceremony at the Pentagon on Sunday, President Joe Biden marked the 21st anniversary of the 9/11 terrorist attacks.
The President laid a wreath honoring victims killed at the pentagon on September 11, 2001, whose names were also read out loud.
In a speech, President Biden called on Americans to stand together to defend democracy.
"No terrorists could touch the wellspring of American power, and it falls to us to keep it safe on behalf of all those we lost 21 years ago, on behalf of all those who have given their whole souls to the cause of this nation every day since," said President Biden.
Vice President Kamala Harris attended a ceremony at Ground Zero in New York City where victims' family members and friends read stories of their lost loved ones.
"Joe, I held your first baby grandson in my arms. You should have been holding him. We love you and we miss you," said Jim Giaccone, who lost his big brother, Joseph Giaccone, in the September 11 attacks.
First Lady Jill Biden spoke at a ceremony in Shanksville, Pennsylvania, where 40 passengers died when United Flight-93 crashed.
"9/11 touched us all—it changed us all. But it reminded us that with courage and kindness we can be a light in that darkness," said the First Lady.
The attacks on the Pentagon and the World Trade Center sparked a global "war on terror" and two decades of fighting in Afghanistan, where U.S. troops withdrew from last year.
The ceremonies also come one month after a U.S. drone strike killed Ayman al-Zawahri, a key Al-Qaeda leader who helped plan the attacks.
Vice President Harris did not give a speech in New York. By tradition, no political figures speak at the ceremony at Ground Zero.