Iranian students have interrupted a speech by President Mohammad Khatami to mark Student Day at Tehran university.
Khatami: Accused of failing to stand up to conservatives
Students chanted "Shame on you" and "Where are your promised freedoms?" to express their frustration with the failure of Iran's reform movement.
A visibly-shaken Khatami defended his record and criticised the powerful hardliners who have closed newspapers and jailed dissidents.
He asked students to stop heckling and accused his critics of intolerance.
Students were once some of President Khatami's strongest supporters.
But they now accuse him of failing to stand up to the conservatives who won parliamentary elections in February.
Correspondents say Mr Khatami is concluding his second and final term in office as a virtual lame duck - having once been seen as a force for great change in the Islamic republic.
"My period is going to be over soon but I do not owe anyone," Mr Khatami told the meeting of about 1,500 students in remarks quoted by Reuters news agency.
"Those power-seeking fanatics who ignored the people's demands and resisted reforms... the ones who destroyed Iran's image in the world, they owe me."
And he defended the record of free speech in Iran, despite the closure of dozens of pro-reform publications in the last four years.
Some students' anger was unabated during the speech
"There is no Third World country where the students can talk to their president and criticise the government as you do now.
"I really believe in this system and the revolution and that this system can be developed from within," he is quoted as saying.
But student leader Abdollah Momeni complained that there was no difference between the president and the authoritarians who thwarted his reform programme.
"Students are very disappointed because they paid a heavy price for supporting
Khatami, but in return they got nothing," he is quoted as saying by Reuters.
A statement distributed by one pro-reform student group at the meeting said: "Unfortunately what Khatami sees as his tolerance was his extreme weakness towards the opponents of democracy".