The body of a suspected hijacker and an air stewardess with her hands tied have been found in the World Trade Centre's wreckage.
Rescuers found the cockpit of one of the planes among the rubble and in it was the body of a man who was not wearing a pilot's uniform.
Close by was the body of a woman believed to be a stewardess, whose hands were tied with wire.
Police could not confirm the bodies had been found.
The discoveries come after the Taliban regime in Afghanistan said prime suspect Osama bin Laden was innocent because the country had no facility to train pilots. The regime claimed a country that could train pilots was responsible.
It is unclear whether bin Laden has been placed under house arrest after a series of conflicting reports from Arabic and Pakistani newspapers.
Officials from the American Justice Department have said each of the planes had a hijacker on board who had trained as a pilot in America.
Flying schools in Florida and Oklahoma are believed to have been the training sites for the pilots, who held licences for jet aircraft.
FBI agents have interviewed staff at the schools, seized files and searched homes in Florida where two of the suspected hijackers are believed to have lived.