PARIS (AP) -- A French judicial official says an anti-terrorism unit is investigating an unsigned letter received by Air China's Paris headquarters threatening reprisals if China does not free jailed Muslims.
A judicial official says the letter was written in English and unsigned. It was received Friday, the opening day of the Beijing Olympic Games.
The official is not authorized to discuss investigations and customarily spoke to reporters on condition of anonymity.
There has been a surge in violence in the mainly Muslim Xinjiang region of far western China coinciding with the Olympics.
(Copyright 2008 by The Associated Press. All Rights Reserved.)