Celebrities have been paying tribute to those who lost their lives on September 11, 2001, on the 15th anniversary of the terrorist attacks.
Stars including Victoria Beckham, Lady Gaga and Ryan Seacrest have all posted messages on Twitter.
Many have tweeted under the hashtag #NeverForget.
-- Lady Gaga (@ladygaga) September 11, 2016
Never forget the lives lost. Never forget the first responders who charged toward danger. Never forget our unity and resolve. #neverforget
-- Arnold (@Schwarzenegger) September 11, 2016
-- Kim Kardashian West (@KimKardashian) September 11, 2016
"What separates us from the animals, what separates us from the chaos, is our ability to mourn people we've never met" #NeverForget15years
-- Sarah Michelle (@SarahMGellar) September 11, 2016
-- Lewis Hamilton (@LewisHamilton) September 11, 2016
As a designer showing on tomorrow's important anniversary, I commemorate the victims of the September 11 attacks. pic.twitter.com/78yB6yeALn
-- Victoria Beckham (@victoriabeckham) September 11, 2016
-- Kourtney Kardashian (@kourtneykardash) September 11, 2016
9/11... We will not forget. https://t.co/w6AoIw80b2
-- Vicky Pattison (@VickyPattison) September 11, 2016
-- Ryan Seacrest (@RyanSeacrest) September 11, 2016
-- Nathan Sykes (@NathanSykes) September 11, 2016
Nearly 3,000 people were killed when passenger jets hijacked by al Qaida terrorists struck the twin towers of the World Trade Centre in New York and the Pentagon outside Washington.
A fourth hijacked plane crashed into a field in Pennsylvania.