President Joe Biden issued a proclamation to lower the flags and have a moment of silence for the attack that killed nearly 3,000 people.

Gov. Roy Cooper has ordered state institutions to fly U.S. and N.C. state flags at half-staff from sunrise to sunset Sept. 11.

"Today, we honor the brave Americans who met the terror of September 11 with extraordinary acts of courage and sacrifice," said President Biden.

U.S. flags typically fly at half-staff in the wake of national tragedies or after deaths of government officials, military members or first responders. They also fly at half-staff on Memorial Day and other national days of remembrance, including 9/11.