Iran must stop banning students from university because of their political views, a human rights group has said.
The group said Iran wanted to coerce students into silence
Human Rights Watch says some students have been barred from registering for university places despite passing the relevant entrance exams.
It said others have been offered places only if they promise to refrain from peaceful political protests.
Human Rights Watch said the Iranian government wanted to coerce students into silence and submission.
Human Rights Watch says according to documents it has obtained, Iran's Ministry of Information - which performs intelligence functions - is orchestrating what it describes as a campaign to deny student activists their right to education.
The group says the government has barred at least 17 students from registering to take up university places over the past year, although graduate programmes had accepted them on the basis of successful competitive entry exams.
The documents, it says, make it clear those decisions were based solely on the students' political backgrounds, not on any educational standards.
All but one of the banned students were outspoken activists or worked with the Islamic Students' Association on their campuses.
Student groups banned
A further 54 students had been allowed to register only after agreeing to sign statements that they would refrain from peaceful political activities.
Human Rights Watch says that since July 2005, the Iranian judiciary has convicted and sentenced 35 students to prison terms for their political activities.
In the same period, 15 student associations had been suspended or banned from operating on campuses.
Iranian student organisations - once extremely active - have been less vocal in their criticism of the government since the violent suppression of major student protests in 1999.
They have continued to be weakened since the election of the current hardline President, Mahmoud Ahmadinejad, last year.