An American flag was unfurled at sunrise over the Pentagon on Friday as the United States marked 25 years since the September 11 attacks, which killed 2,977 people.
The ceremony in Arlington, Virginia, honoured the 184 military personnel and civilians who died when hijackers crashed American Airlines Flight 77 into the headquarters of the US Department of Defence.
President Donald Trump was due to attend a separate commemoration at the Pentagon later in the morning, alongside Secretary of War Pete Hegseth and Air Force General Dan Caine, chairman of the Joint Chiefs of Staff.
The flag ceremony formed part of a day of memorial events across the country, including observances in New York and at the Flight 93 National Memorial in Pennsylvania.
In a proclamation issued on Wednesday, Mr Trump designated September 11 as Patriot Day and called for the US flag to be flown at half-mast in honour of those killed in the attacks.
He had earlier joined first responders, Gold Star families and the Tunnel to Towers Foundation at an event on the Ellipse outside the White House.
The gathering featured a 21ft steel beam recovered from the South Tower of the World Trade Centre. Weighing almost 17,000lb, it had travelled through 21 states as part of the Steel Across America memorial tour.
The beam was due to continue to New York for a procession commemorating firefighter Stephen Siller, who died while responding to the attacks.
The September 11 attacks began when four passenger aircraft were hijacked and used as weapons. American Airlines Flight 77 struck the Pentagon at 9.37am, while two aircraft hit the World Trade Centre in New York and a fourth crashed in a field near Shanksville, Pennsylvania, after passengers confronted the hijackers.
The 25th anniversary is also being marked by a new installation at the National September 11 Memorial and Museum in New York. “Our Flag Was Still There” includes the large flag placed over the Pentagon on September 12, 2001, by soldiers from the 3rd Infantry Regiment and Arlington firefighters.
The Pentagon flag unfurling has become an annual feature of the military headquarters’ September 11 observance, providing a solemn opening to ceremonies honouring those who died and the emergency workers who responded.
