Unlike Egypt, they don't have the army backing the greens up.
From news article:
TEHRAN – Agence France-Presse
Clashes erupted between regime backers and "apparent" supporters of Iran's opposition at a funeral in Tehran Wednesday of a person killed in anti-government protests, state television reported.
"Students and people participating in the funeral of martyr Sane'e Zhale in Tehran Fine Arts University are clashing with a few apparently from the sedition movement," the television website said.
It said that regime backers by "chanting slogans of 'Death to Monafeghin'(rebels) forced them (opposition supporters) out of the scene."
The clashes erupted when pro-regime backers, including members of parliament and Revolutionary Guards, held a demonstration during the funeral of Zhale chanting "Death to America! Death to Israel! Death to Britain! Death to Monafeghin! Death to Mousavi and Karroubi!" state media reported.
Zhale, a Sunni Kurd, was slain during Monday's anti-government protests staged by supporters of opposition leaders Mir Hossein Mousavi and Mehdi Karroubi. But he became the centre of a dispute Wednesday, with regime-backers insisting he was member of the volunteer Islamist Basij militia, while the opposition said he came from their ranks.
"This university student (Zhale) was shot around Enghelab Square by small arms fire. He was a student of fine arts and defender of the regime," said state news agency IRNA. Opposition website Rahesabz.net said Zhale was "pro-Mousavi and a member of the Green Movement," referring to the opposition movement spearheaded by Mousavi which refuses to acknowledge the presidency of Mahmoud Ahmadinejad. "His family was under pressure to say he is Basiji and pro-government," the website said.
Zhale was one of the two people killed on Monday when riot-police and opposition backers clashed in Tehran during an anti-government demonstration