Ceremonies in the U.S. have marked the anniversary of the September 11 terrorist attacks with moments of silence and the reading of victims' names.

Bells tolled and bagpipes played in New York at the moment eight years ago when the first of two hijacked airliners slammed into the World Trade Center.  

President Barack Obama took part in a ceremony on the South Lawn of the White House, while Vice President Joe Biden spoke at the service in New York.

Nearly 3,000 people died on September 11, 2001, in a coordinated al-Qaeda attack involving four hijacked planes.  One of them crashed into the Pentagon, where Mr. Obama plans to attend a wreathlaying on Friday.

Services are also planned in Shanksville, Pennsylvania, the crash site of United Airlines Flight 93.  That aircraft went down after passengers fought hijackers and presumably stopped the plane from hitting its intended target.