President Barack Obama and Vice President Joe Biden will participate in public and private events on Tuesday to mark the 11th anniversary of the September 11 terrorist attacks, the White House announced on Monday evening. In the morning, Obama, first lady Michelle Obama and White House staff will gather on the South Lawn of the White House to observe a moment of silence. Later in the morning, the President and First Lady will travel to the Pentagon Memorial to attend an observance ceremony. In the afternoon, Obama will travel to Walter Reed National Military Medical Center and visit with wounded soldiers, who are being treated at the hospital, and their families. In the morning, Biden will travel to Somerset County, Pennsylvania, to deliver remarks at the Flight 93 National Memorial Commemorative Service to honor the passengers and crew who died there. Later in the afternoon, Obama and Biden will meet with Secretary of Defense Leon Panetta in the Oval Office.