US marks 21st anniversary of 9/11 terror attack

The 9/11 anniversary commemoration at ground zero begun with a tolling bell and a moment of silence, 21 years after the start of the deadliest terror attack on U.S. soil. Victims' relatives and dignitaries are gathering Sunday at all three places where hijacked jets crashed on Sept. 11, 2001, the World Trade Center in New York, the Pentagon and a Pennsylvania field.

The attacks killed nearly 3,000 people. Vice President Kamala Harris attended the ceremony in New York, but by tradition, no political figures speak at the ground zero ceremony. The observance centers, instead, on relatives reading aloud the names of the dead. President Joe Biden spoke at the Pentagon, while first lady Jill Biden attended the memorial in Shanksville.