Police in Toronto have arrested a man known to have flown from Europe to North America on the day of the terror strikes on New York and Washington.
FBI papers show the man flew from Germany to Chicago on the day of the terrorist attacks.
His flight, believed to be a Lufthansa plane, was diverted to Toronto in Canada after terrorists hijacked their planes.
The man was arrested in Toronto on suspicion of carrying false passports.
An FBI spokesman said the man appeared to have used several aliases, and was carrying three Yemeni passports bearing different dates of birth.
His true age and nationality were not known, the spokesman said.
CNN reported the man was believed to be an employee of Lufthansa and was carrying airline uniforms in a bag, but the FBI spokesman said those details were not clear.
He said the FBI was not revealing how many people in total had now been arrested in connection with the terrorist attacks.
PA