Supporters of Mir Hossein Mousavi are planning a new demonstration in Tehran in protest at what they see as a fraudulent presidential poll in Iran.

The planned rally comes after overnight raids on university dormitories in several Iranian cities and as two pro-reform figures were arrested.

Iran's Supreme Leader, Ayatollah Ali Khamenei, has sought to calm tensions and called for an end to rioting.

Mahmoud Ahmadinejad was re-elected last week with almost two-thirds of votes.

Protests have grown since his re-election was confirmed on Saturday, with huge demonstrations in Tehran and clashes between protesters and security forces. Eight people have been killed.

The latest opposition demonstration is expected to wind its way though central Tehran in mid-afternoon local time. A similar march on Tuesday is thought to have passed off peacefully, although few details have emerged.

Iran has imposed tough new restrictions on foreign media, requiring journalists to obtain explicit permission before covering any story. Journalists have also been banned from attending or reporting on any unauthorized demonstration, BBC reported.