A senior Iranian intelligence official has warned Iranian academics to be careful about what they say when attending conferences overseas.
Haleh Esfandiari has been jailed on charges of spying
The anti-espionage chief in Tehran, said professors were under threat from foreigners out to obtain information.
His remarks follow the detention of two Iranian-Americans in Tehran on espionage charges.
The official said spies were also trying to infiltrate sensitive Iranian areas by contacting influential people.
He said Iran had destroyed several spy networks set up by American and British intelligence.
The official said Iran's professors were under threat from foreigners who were trying to obtain information by inviting them to scientific seminars.
He said not every contact or funding from abroad was innocent and Iranian academics should be careful about giving interviews or information to foreigners.
The same intelligence official said the CIA and British intelligence were involved in spying, but Iran had destroyed several of their networks that were trying to set off bomb blasts, conduct terrorism and kidnappings and also film and photograph sensitive sites.
The official complained spy networks were also targeting ethnic minorities and attempting sabotage in areas on Iran's western borders.
Earlier this month, a former nuclear negotiator for Iran now working in a research centre was arrested on suspicion of spying.
Two Iranian-American academics have been charged with spying and a journalist faces the same accusation.
The judicial spokesman, Ali Reza Jamshidi, said both Haleh Esfandiari and Kian Tajbaksh were formally charged with spying, acting against Iran's national security and conducting propaganda against the Islamic Republic.
And Iran lodged an official protest on Sunday against the US government for allegedly sending spies to Iran.