James Laychak, president of the Pentagon Memorial Fund, avoided commenting directly on the allegations, but applauded the Defense Department's willingness to conduct an independent review.

WSJ: Dover Military Mortuary Sent Some 9/11 Remains to Landfill

The mood was much more somber at the Pentagon memorial a few miles away, where 184 people died when a hijacked American Airlines Flight crashed on September 11, 2001.

CNN: Americans take to the streets amid news of bin Laden's death

The Pentagon memorial, opening Thursday, includes a bench, a tree and a pool for each of the 184 people killed there when another hijacked airliner crashed into the building.

CNN: Creating 9/11 memorials a slow process

Defense Secretary Robert Gates will also participate in the memorial service, but he will not speak, Pentagon spokesman Geoff Morrell said.

CNN: Investigators look for missed signals in Fort Hood probe

Seven years after the September 11 attack on the Pentagon, the wall is designed to remind visitors of the youngest and oldest victims, wrapping the memorial in symbolic imagery.

CNN: Pentagon 9/11 memorial honors victims in symbols, concrete

The couple laid a wreath of white flowers at a new marble memorial to the 40 passengers and crew of the lost plane, before moving on to the Pentagon, outside Washington DC, where another wreath was laid.

BBC: 9/11 anniversary: Sombre US honours victims 10 years on