Iranian police have clamped down hard on mounting opposition protests in the capital, Tehran.
Crowds had gathered spontaneously and sporadically in and around the main Azadi Square. After nightfall, demonstrators used the cover of darkness to try and outwit the security forces.
“The security forces used tear gas to try and control and disperse the protesters. There has been a lot of violence and many people have been arrested. We heard a lot of shots being fired in a street nearby,” one eyewitness told euronews.
Police blocked off Eskandari Street, the main thoroughfare where most of the protesters were gathering.
Officers on motorbikes then went in to disperse the crowds.
The unrest comes a day after websites linked to opposition leaders Mir Hossein Moussavi and Mehdi Karroubi said they had been put in prison. The government denied this, saying both men are at home.
They have been under effective house arrest since events in Tunisia and Egypt last month led them to call for similar popular protests in Iran.