The commemoration of the 17th anniversary of the September 11 terror attacks has begun at the World Trade Centre in New York with a moment of silence and tolling bells.
Victims' relatives, survivors, rescuers and dignitaries gathered on the memorial plaza where the twin towers once stood as the ceremony started at 8.46am on Tuesday. That is the time when a hijacked plane slammed into the World Trade Centre's north tower.
Then victims' loved ones began reading the names of the nearly 3000 people killed when four hijacked planes crashed into the trade centre, the Pentagon and a Pennsylvania field on September 11, 2001.
US President Donald Trump and first lady Melania Trump are at the 9/11 memorial near Shanksville, Pennsylvania.
Vice President Mike Pence is attending a ceremony at the Pentagon.
