Obamas observe 9/11 anniversary moment of silence - 13 WTHR Indianapolis

President Barack Obama and first lady Michelle Obama are at Arlington National Cemetery visiting the graves of service members killed in Afghanistan and Iraq.

The visit to the burial ground across the Potomac River from the White House is part of the president's observance of the 11th anniversary of the 9/11 terrorist attacks.

The Obamas quietly walked between rows of graves at Section 60, which contains the remains of the most recent war dead. Pausing at several graves, Obama placed presidential "challenge" coins at the base of the headstones. The first headstone listed the names of 10 victims of an Oct. 26, 2009, helicopter crash in Afghanistan.

Earlier, the Obamas placed a wreath at the Pentagon and observed a moment of silence on the White House South Lawn.

At the Pentagon memorial service, Obama said the U.S. is safer and its people resilient on the 11th anniversary of the 9/11 terrorist attacks.

Aided by a Marine honor guard, Obama placed a white floral wreath on a metal stand above a concrete slab that said "Sept. 11, 2001 - 9:37 am." A moment of silence began at precisely 9:37 a.m.

In remarks at the Pentagon, Obama recalled a day "when grief crashed over us like an awful wave."

In the afternoon, the president was scheduled to visit wounded soldiers and their families at Walter Reed National Military Medical Center.

Vice President Joe Biden was traveling to Pennsylvania to deliver remarks at the Flight 93 National Memorial Commemorative Service.

(Copyright 2012 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.)