Under gray, rainy skies, ceremonies in the U.S. have taken place on the eighth anniversary of the September 11 terrorist attacks.
President Barack Obama called on the nation Friday to renew its resolve against the perpetrators of the al-Qaida operation, which killed nearly 3,000 people in 2001.
Memorials in New York, in the Washington area, and at Shanksville, Pennsylvania marked the day when hijackers crashed airliners into the World Trade Center, the Pentagon, and a Pennsylvania field.
Speaking at the Pentagon, Mr. Obama said on a day when terrorists tried to sap the nation's confidence, Americans instead should remember how they came together. The memorial events included moments of silence, the tolling of bells, and the reading of victims' names.
The September 11 attacks began when two airliners crashed into the twin towers of the World Trade Center, followed by a plane flown into the Pentagon. A fourth aircraft went down in Pennsylvania, after passengers fought with their hijackers.