Interior Minister Abdolvahed Mousavi-Lari visited Tehran University after violent clashes between students and police and right-wing vigilantes.
He told them those responsible for attacking the students would be punished and students arrested in the disturbances would be freed.
But the students are demanding President Mohammad Khatami visit them to resolve the situation.
Police closed roads leading to university dormitories, where thousands of people were reported to have gathered in a show of support for the students.
Dormitories stormed
The violence began on Thursday when right-wingers attacked students demonstrating against new press laws and the subsequent closure of Salam, a liberal newspaper that supported the moderate President Khatami.
Witnesses said that when police arrived they used tear gas and batons to storm dormitories at the Amirabad campus.
A prominent reformer, Ibrahim Yazdi, told the BBC at least three students had been killed and hundreds were injured. Security personnel were also said to be among the wounded.
There has been no official confirmation of the deaths.
An Iranian journalist, who entered the campus before the violence broke out, said dormitories were burned, windows smashed and several cars and motorcycles destroyed.
But the Ministry of the Interior has said it did not authorise the operation and that all arrested students would be released apart from the demonstration organisers.
Ministry spokesman Bahaeddin Sheikholeslam said: "Police, without co-ordination with the interior ministry, intervened in the clashes and arrested a number of students."
And the higher education ministry has severely criticised the police actions, linking them to killings of intellectuals last year.
Mounting tension
The student protest was sparked by a decision of the conservative Special Court for Clergy to ban Salam indefinitely for disturbing public opinion, endangering national security and violating Islamic principles.
The ban was made possible by a new law on press freedoms.
BBC Middle East Correspondent Jim Muir said the violence reflected the mounting tension between the reform movement and hard-line conservatives.
Iran's press has enjoyed relative freedom since President Khatami's election in 1997 but has come under mounting pressure from hardliners in recent months.
Two journalists were arrested last month, on charges of spreading anti-Islamic propaganda.
Country profiles
Iran closes down newspaper
(07 Jul 99 | Middle East)
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