Fresh clashes have erupted in Tehran during the funeral of a student killed in anti-government protests on Monday, Iranian state television says.
Rival groups of pro- and anti-government protesters both claim the dead man as one of their supporters.
Sanea Jaleh, 26, was among two people killed during Monday's protests, when thousands of opposition members rallied for the first time in more than a year.
The protests come amid a wave of unrest in the Middle East and North Africa.
Wednesday's clash took place during Mr Jaleh's funeral procession, which started at Tehran University in the centre of the capital, broadcaster Irib reported.
"Students and the people attending the funeral ceremony... have clashed with a limited number of people apparently linked to the sedition [opposition] movement and forced them out by chanting slogans of death to hypocrites," the report on the state-run channel said.
It gave no details of any injuries.
The BBC's Mohsen Asgari, who attended the ceremony in Tehran, said he did not see any major clashes. But he said police forces had blocked all the roads leading to the university and were only allowing in pro-government supporters.
On Monday, thousands of supporters of opposition leaders Mir Hossein Mousavi and Mehdi Karroubi took to the streets of Tehran to show solidarity with the uprisings in Tunisia and Egypt, which have both succeeded in toppling their unpopular leaders.
Two people were killed and several wounded during Monday's clashes with riot police in Tehran. Some 1,500 people have been detained, opposition groups say, but official figures put the number at 150.
'Pay the price'
Following the deadly clashes, Iranian MPs called for the two opposition leaders to be tried and executed.
But Mr Karroubi and Mr Mousavi - who are both being held under de facto house arrest - issued defiant statements via their websites on Wednesday.
"I am not afraid of any kind of threat and as a soldier of this great nation for the past almost 50 years, I am ready to pay any price," Mr Karroubi said on his official site Sahamnews.org.
In a separate statement on his own website, Kaleme.com, Mr Mousavi praised the protesters for Monday's rally.
"The glorious rally on 25 Bahman (14 February) is a great achievement for the great people of a great nation and for the Green Movement," he said, referring to the opposition movement and its supporters.
The protests were the first anti-government demonstration since February 2010, when similar agitation was crushed by security forces and militiamen.
Opposition supporters maintain that the re-election of President Ahmadinejad in June 2009 was rigged.
Many of the slogans chanted by protesters on Monday were aimed against the most senior figure in the Iranian regime - Supreme Leader Ayatollah Ali Khamenei.
He is seen by them as the power behind the opposition crackdown, Mr Ahmadinejad's disputed re-election, and behind many of the president's domestic and foreign polices which have brought hardship to Iranians.
President Ahmadinejad said on Tuesday that the latest opposition protests seen in Iranian cities were "going nowhere" and vowed to punish their organisers.
US President Barack Obama sharply criticised the authorities' response.