Watch live as President Biden lays a wreath at the Pennsylvania Flight 93 memorial

US President Joe Biden is attending a 9/11 memorial ceremony in Shanksville, Pennsylvania to pay his respects to all those who lost their lives in the attacks some 20 years ago.

Biden has already been at the memorial ceremony at Ground Zero in New York – where he was joined by former Presidents Obama and Clinton at the site of the Twin Towers that both collapsed during the attacks.

George W Bush, who was president of the United States when the terrorist attacks occurred, spoke of being vigilant of enemies “from within” when making a speech earlier today.