Thousands of supporters of hardline Iranian President Mahmoud Ahmadinejad and his main moderate challenger clashed in Tehran on Friday, a week before Iran's presidential election, Reuters reported.
After sporadic fist-fights and shoving between the supporters of Ahmadinejad and former prime minister Mirhossein Mousavi, police forced the demonstrators to disperse and no one was badly hurt, one witness said.
"Freedom is impossible with Ahmadinejad," chanted the thousands of mainly young Mousavi supporters in Tehran's Vali-ye Asr square, another witness said, asking not to be named.
"Bye, bye Ahmadinejad. Leave us alone," they shouted, most carrying green flags -- the campaign colour of Mousavi and associated with descendants of the Prophet Mohammad.
Scores of young Iranians have been wearing green wristbands, scarves and T-shirts in the run-up to the June 12 vote.
With more than 60 percent of Iranians under the age of 30, their votes will be crucial.
Ahmadinejad is being challenged by Mousavi, former parliament speaker Mehdi Karoubi and conservative former head of Iran's elite Revolutionary Guards, Mohsen Rezaie.
Mousavi has accused Ahmadinejad of damaging Iran's dignity since coming to power in 2005.
Other youths tried to hand out pictures of Ahmadinejad and then supporters of both candidates started to shout at each other, the first witness said.
"Ahmadinejad is our hero. Our next president is our brave Ahmadinejad," chanted the president's supporters, while waving Iran's national flag.
The president said on Wednesday that Mousavi was backed by reformist former President Mohammad Khatami and his pragmatic predecessor, Akbar Hashemi Rafsanjani.
He accused Khatami, Rafsanjani and Mousavi of trying to weaken the Islamic state by wanting a policy of "detente" with the West.