People in the United States are marking the 20th anniversary of the 9/11 terrorist attacks.
On September 11, 2001, hijackers flew two planes into the Twin Towers of the World Trade Center in New York City. A third aircraft crashed into the Pentagon near Washington DC, and a fourth plane into a field in Pennsylvania. The attacks killed 2,977 people.
In New York, a memorial ceremony started at around 8:30 a.m. local time at the site of the World Trade Center.
Bereaved families as well as President Joe Biden, the First Lady, and former presidents Barack Obama and Bill Clinton were in attendance.
The participants offered prayers six times at the instant the four planes had crashed into their targets and when each of the Twin Towers had collapsed.
The names of the victims were also read aloud one by one.
The names are engraved on parapets surrounding two memorial pools. Bereaved families were seen placing hands on the names of their loved ones they had lost and offering flowers to them.
Sugiyama Harumi, the wife of a Japanese victim, also attended the ceremony. Her husband, Yoichi, had been working at the office of a bank in the South Tower at the time of the attack.
Sugiyama told NHK that standing at the site, she really felt 20 years had passed. She said she is grateful to her husband for watching over her for these years and that she feels as if he is congratulating her on her hard effort to live without him.
Memorial ceremonies were also held in Shanksville, Pennsylvania, where all those on board the hijacked plane had died, as well as at the Pentagon, where passengers and Defense Department officials had died.
The United States withdrew all its forces from Afghanistan in August, 20 years after it launched a military campaign in the country in the wake of the 9/11 attacks. The withdrawal demonstrated the turning point of the US strategy over the 20-year "war against terrorism".