Student demos are kept under wraps by Iran

Iranian authorities took concerted steps today to keep major student protests secret from the rest of the world.

Security forces and pro-government militiamen with batons and tear gas clashed with thousands of opposition protesters in the Iranian capital today.

Militiamen waded into the crowds of protesters outside Tehran University, beating men and women over the head with batons, while security forces fired tear gas, witnesses said.

But it was unclear whether demonstrations had also broken out inside campuses because mobile phones in the area were shut down and fences covered with banners. Foreign media workers were banned from leaving their offices.

At least two women supporters of opposition leader Mirhossein Mousavi were arrested in the "student day" demonstrations, to commemorate the killing of three students in 1953.

The 12 June presidential election, which secured President Mahmoud Ahmadinejad's re-election, sparked Iran's worst unrest since the Islamic revolution three decades ago and exposed deep divisions in the establishment. Authorities deny allegations of vote-rigging.

One witness said that police had fired tear gas at protesters in Tehran's Vali-ye Asr square who were chanting "Death to the dictator" and "Do not be scared - we are all together."

Mr Mousavi said the authorities were "fighting with shadows in the streets" and that the protest movement was still alive.

"If you silence all the universities, what can you do with the situation of the society?" he asked on his website.