Academic freedom suffered numerous violations around the globe during 2001, according to the New York-based Human Rights Watch.
"Oppressive governments punished academics for exercising their right and responsibility to question and criticise their societies," says its annual report.
"In a troubling development, several armed opposition groups also resorted to this method of silencing their critics. Ideological controls over the nature and content of academic material were apparent around the world, and students who in many countries served as leaders in social development were targeted.
"Many governments also blocked the access of vulnerable and disenfranchised segments of their population to education."
Repression was not confined to third-world dictatorships. In the wake of the attacks on New York City and Washington, several academics in the United States and Canada came under official or public pressure for questioning aspects of their governments' past or projected policies, HRW says.
Since the report was written, the University of South Florida has come under pressure to reinstate a Palestinian computer science professor alleged to have links with so-called terrorist groups. Sami Al-Arian was fired on December 19 after the FBI and the Immigration and Naturalization Service claimed that a university-based think-tank he founded was a fundraising front. Professor Al-Arian has not been detained or charged with any crime. He continues to protest his innocence.
The university's senate has lodged a protest at the dismissal, which was carried out by the university's president to safeguard it from adverse publicity.
Sam Zia Sarifi, director of HRW's academic freedom programme, said:
"Governments around the world seem to have learnt exactly the wrong lesson from the events of September 11, insofar as there has been a general chill on critical academic work under the guise of fighting supposed Islamist extremism."
He added: "We've also seen governments of many Islamic countries, from North Africa to the western-oriented states of the Middle East, to Uzbekistan, and through Pakistan, Bangladesh, Indonesia, and Malaysia, use the excuse of fighting terror to clamp down on academic criticism.
He said that the events of September 11 should have taught "the need for exactly the opposite action: such extremism thrives in conditions of cultural poverty, where young people are not taught how to think clearly".