Iran's security forces fired teargas and clashed with opposition supporters in Tehran on Tuesday, where demonstrators were rallying to demand the release of two opposition leaders, according to an opposition website.

"Security forces and people in civilian clothes clashed with demonstrators in Tehran to disperse them," opposition website Kaleme reported.

Sahamnews, another opposition website, reported large numbers of security personnel stationed at main streets and squares in Tehran "to prevent gathering of opposition supporters."

Former presidential candidates Mirhossein Mousavi and Mehdi Karoubi have not been seen in public since they called for a rally on Feb. 14, during which thousands of their supporters took to the streets to support uprisings in the Arab world.

Open gallery view Iranian protestors attending an anti-government protest as a garbage can is set on fire, in Tehran, Iran, Monday, Feb. 14, 2011. Credit: AP

Opposition websites had called for Tuesday's rally to demand their release.

Opposition website Sahamnews reported on Monday that Mousavi and Karoubi had been jailed along with their wives. Judiciary officials deny they have been jailed but say they have been kept at home and barred from contact with the outside world.