"Enrichment is our natural right," the university students shouted, along with the habitual "Death to America".

Most of them also wore headbands showing their readiness for "martyrdom".

On Sunday, Iranian lawmakers, passed a bill backing the resumption of uranium enrichment, as the government left the door open for further negotiations with Europe over the controversial practice.

The motion was also passed to calls of "Death to America."

Iran's parliamentary speaker, Gholam Ali Hadad Adel described the vote as a "message addressed to foreign countries that parliament will not give in to intimidation". The text tells the government "to take action for the country to master civilian nuclear technology, especially in the fuel production cycle".