Official commemorations are underway to mark the 20th anniversary of the 9/11 attacks on the United States.
The ceremony in New York began with a minute of silence at 08:46 EST (13:46 BST) – the exact time the first plane hit the World Trade Center’s North Tower in 2001.
Thousands of people have gathered across the United States to commemorate the solemn occasion.
On Saturday, President Joe Biden will visit all three terror attack sites: New York, Pennsylvania, and Virginia.
A minute of silence will also be observed to commemorate the moments when the second plane crashed into the World Trade Center’s South Tower, when a third plane struck the Pentagon in Virginia, when a fourth hijacked plane crashed into a field in Pennsylvania, and finally when the World Trade Center towers collapsed.
In total, 2,977 people were killed in the attacks, which occurred when suicide bombers hijacked and crashed US passenger jets.
President Biden paid tribute to the victims and the grief that has followed their relatives for two decades in a video released on the eve of the anniversary.
“No matter how much time has passed, these commemorations bring everything back to you as if you just got the news a few seconds ago,” he said.
More on the 11 September attacks
- What happened on 9/11?
- 9/11 victim’s son on day world
- From United to Disunited States – the years since 9/11
Earlier in the day, a vigil was held at the Fire Department of New York memorial wall, a 56-foot-long bronze wall honouring the 343 firefighters killed on the day of the attacks.
In total, 441 first responders were killed in the attacks, making it the deadliest attack on emergency personnel in American history.
“We honour all those who risked and lost their lives in the minutes, hours, months, and years that followed,” Biden said in his speech on Friday.