The United States is marking the 12th anniversary of the 9/11 terrorist attacks.
The White House says President Barack Obama will take part in ceremonies, including a moment of silence on the White House lawn to pay homage to the nearly 3,000 people killed in attacks on the United States using hijacked airplanes on September 11, 2001.
Commemorations are planned at the three sites where four hijacked planes crashed -- in New York City and Washington, D.C., and rural Shanksville, Pennsylvania.
The White House said Obama's national security team is taking steps to prevent terrorist attacks related to the anniversary.
Obama discussed preparedness and security with his team on September 10.
With reporting by AP