Supporters and opponents of Iranian President Mahmoud Ahmadinejad clashed in a Tehran square on Saturday evening and some cars were set on fire, a witness said, in a sign of rising tension ahead of the June 12 election.
The incident took place as rival supporters followed a televised debate between Ahmadinejad and pro-reform challenger Mehdi Karroubi on big screens at Sarv square in northwestern Tehran, the witness told Reuters.
It was the second night of sporadic unrest in the capital, after thousands of supporters of Ahmadinejad and another of his moderate challengers in the presidential election scuffled elsewhere in the capital on Friday evening.
Mainly young supporters of the election hopefuls have poured into the streets of Tehran during evenings as the election approaches, shouting, honking car horns and waving pictures of their candidates.
With more than 60 percent of Iranians under the age of 30, their votes will be crucial.
Ahmadinejad is being challenged by former parliamentary speaker Karroubi, former Prime Minister Mirhossein Mousavi, and the conservative former head of Iran's elite Revolutionary Guards, Mohsen Rezaie.
Mousavi, a moderate who is hoping to win votes from both reformers and conservatives, is seen as Ahmadinejad's main opponent in the election.
In a heated debate, Ahmadinejad and Karroubi traded allegations on issues ranging from the economy of the world's fifth-largest oil exporter to Iran's foreign relations and views on the Holocaust and Zionism.
Ahmadinejad hit back at critics accusing him of stoking inflation with profligate spending of petrodollars since he came to office in 2005, saying the rate was declining and would soon fall below 10 percent, compared with 18 percent in March.
The rate, which peaked at nearly 30 percent in October, was about 11 percent when Ahmadinejad came to power four years ago pledging to share out Iran's oil wealth more fairly and reviving the values of its 1979 Islamic revolution.
He said inflation had "come down and was less than 15 percent now," adding that pensions had jumped by "nearly 256 percent".
According to central bank figures, Iran is currently reeling under inflation of around 25 percent, which several economists attribute to Ahmadinejad's expansionist policies.
The unemployment rate is around 12.5 percent.
Karroubi, 72, is dubbed the "sheikh of reforms" in Iran. He tried to counter Ahmadinejad in the occasionally fiery debate, saying the "government must be honest to the people" and said "lying is the worst sin in Islam."
Dismissing the figures given by Ahmadinejad, the cleric said: "I have been working in the parliament for 16 years ... all the figures that you have given are contradictory to the ones we have seen over the years."
"People are aware of the realities ... when they purchase meat they feel the inflation, no matter what the government says" said Karroubi.
During the debate, Karroubi was scathing about Ahmadinejad's foreign policy.
Karroubi pointed out that Latin American president Hugo Chavez, whose ties with Iran have grown under Ahmadinejad, had hugged Saddam Hussein with whom the Islamic republic fought a eight-year war in the 80s.
And in an apparent attempt to whip up nationalist sentiment, he angrily attacked Ahmadinejad for having attended a Gulf Cooperation Council summit and sat under a sign which allegedly said Arab Gulf countries.
"We should hit ourselves hard on the head over this," the cleric said expressing a feeling of great shame usually uttered in Persian.
A composed Ahmadinejad, who often chuckled at Karroubi's remarks, defended himself by saying that the term Arab refers to the countries and not the Gulf itself.
Ahmadinejad's critics say his fiery anti-Western speeches and questioning of the Holocaust have isolated Iran, which is at odds with the West over its disputed nuclear program.
Iran says it is for electricity generation, but a number of Western countries believe the aim is to build nuclear weapons.
In his debate with Ahmadinejad on Wednesday, Mousavi accused him of humiliating the Iranian nation by adopting an "extremist" foreign policy causing an Iranian passport to be perceived on the same level as a Somali one
Ahmadinejad accuses his rivals of trying to weaken the Islamic state and going against the teachings of Ayatollah Khomeini, the leader of the country’s Islamic revolution, by advocating detente with the West.