IRAN'S controls are not as pervasive as China's, he noted, but Teheran is clearly stepping up its online censorship.

Of late, world leaders have expressed growing concern over Iran's brutal crackdown on dissidents. Canada has been among the most vocal, outright rejecting Iran's call to 'stay out' of its internal politics.

Last week, Canada's charge d'affaires was reportedly berated by Teheran over what Iranian authorities believed was Ottawa's support for Mr Rohozinski's 'efforts to spread insurrection in Iran' with his software.

Mr Rohozinski denied any direct government ties, but his first clients include the BBC and the US Broadcasting Board of Governors responsible for Voice of America.

On Thursday, US Senators vowed to help Iran's opposition defeat restrictions on news and the social networking Internet sites, as well as boost funding for US-backed radio news broadcasts into Iran.

'We want the Iranian people to be able to stay one step ahead of the Iranian regime, getting access to information and safely exercising freedom of speech and freedom of assembly online,' said Independent Senator Joe Lieberman. -- AFP