TEHRAN: Iran's cyber police force is poised to launch a new crackdown on software that lets many Iranians circumvent the regime's Internet censorship, media reported on Sunday.

The operation will target VPNs, or Virtual Private Networks, which use a secure protocol to encrypt users' data, foiling online blocks put in place by Iran's authorities, according to the head of the specialised police unit, Kamal Hadianfar.

"It has been agreed that a commission (within the cyber police) be formed to block illegal VPNs," he was quoted as saying in a report originally published by the Mehr news agency.

"About 20 to 30 percent of (Iranian internet) users use VPN," or more than seven million people out of the country's 36 million web users, he added.

Legal VPNs would only be used by "the likes of airlines, ministries, (state) organisations and banks," he said -- and even they would be monitored by the commission.

Iran has long tried to stop its population accessing millions of foreign websites authorities see as undermining the Islamic regime, including Facebook, Twitter, the online pages of the BBC and CNN, many torrent sites, blogs, and pornographic hubs.

"Some websites are obscene and others are officially hostile towards the Islamic republic's system. (Thus), in the interest of the people and in order to prevent the collapse of families... there is blocking of the Internet," Hadianfar said.

The Islamic republic's suppressing of the Internet has intensified since President Mahmoud Ahmadinejad was returned to office in a disputed 2009 election that sparked a wave of anti-government protests, mostly organised online.

Many Iranian Internet users are used to getting around the censorship through the use of either VPNs or IP proxy software.

But they are being increasingly hemmed in by more sophisticated measures being deployed by officials, who are planning a closed "Islamic Internet" that some believe could be designed to supplant the world wide web within Iran.

Iran's telecommunications ministry last month reportedly ordered the country's banks, insurance firms and telephone operators to stop using foreign e-mail accounts such as Gmail to communicate with clients, and instead adopt e-mail domains ending with .ir, which belongs to Iran.

Authorities have also several times recently slowed connections through VPNs to an excruciatingly slow speed to dissuade their use, and have occasionally halted all access to Gmail, Yahoo mail and other foreign communication services.

Such tactics have drawn criticism, even from within the regime, with politicians lamenting the obstacle they present for import/export merchants, students and researchers.

Iran's former president Akbar Hashemi Rafsanjani, a sidelined pragmatic figure who now heads an advisory council to supreme leader Ayatollah Ali Khamenei, was quoted two weeks ago by the ISNA news agency as saying Facebook was a "blessing".

"We see that a Facebook page costing nothing can outstrip several television and radio outlets, and can influence millions of people," he was quoted as saying.

Trying to block the Internet -- and banned although widely-watched foreign satellite television channels -- was futile because users will always find ways around, he said.

"People cannot be stopped in their pursuit of information," he was quoted as saying.

Rafsanjani said some in Iran's regime may dislike that, "but if we think about the happiness of human beings, we see that if social media did not exist, movements against tyranny and oppression would be endangered."

The United States, Iran's arch foe and the genitor of the Internet, is seeking to tear open what President Barack Obama in March termed the Islamic republic's "electronic curtain".

He announced measures to encourage US software makers to market communication programmes in Iran. And in April, he ordered new sanctions targeting companies that help Iran and its ally Syria oppress their people with surveillance software and monitoring technology.

The New York Times newspaper reported early this month that Obama had also accelerated cyberattacks on Iran's nuclear programme, including the Stuxnet virus that destroyed hundreds of uranium enrichment centrifuges in Iran's Natanz facility.

Iran has said a new computer virus dubbed Flame that hit servers run by its oil sector appeared to be linked to Stuxnet, and it has cast suspicion on the United States as the perpetrator. -- AGENCIES