Flag from 9/11 destroyed in fire at Flight 93 memorial in Pennsylvania

A flag that flew over the US Capitol on September 11, 2001, was destroyed in a fire at the Flight 93 National Memorial in Shanksville, Pennsylvania.

Friday's fire destroyed the park's headquarters complex. State police and the park service are conducting a joint investigation into the blaze, the cause of which hasn't been determined, the park service said.

Park staff completed an initial inventory and said that, in addition to the flag, the losses included a handful of personal items of passengers and crew.

Destroyed items included DVDs of the annual commemoration ceremony and meetings of the Flight 93 National Memorial Federal Advisory Commission, as well as about 100 tribute items left by visitors since 2001.

Park staff, however, managed to save hundreds of oral histories and a photo collection.

The buildings comprised the park's headquarters, with conference facilities, storage space and the superintendent's office. The under-construction memorial and visitors centre are about 3km away and were unaffected.