Google and Facebook set up Farsi versions of their websites and services yesterday, saying that they were responding to the importance of the internet as a communications tool for Iranians during the turmoil in the country.

The web has made it possible for many Iranians to communicate since last week’s disputed election, and the international media have used services such as Twitter and YouTube in their reporting of the protests.

Recognising the internet’s crucial role in events in Iran, Google added a Farsi dictionary to Google Translate, its online translation service. It will enable millions of Iranians who are trying to get their message out to the wider world to translate any text, from blog posts to Twitter messages, from Farsi into English and vice versa. Users simply insert text on to the Google Translate website and it is translated at the click of a button.

A Google spokesman said: “This is not a political statement. There’s a huge amount of interest in the events in Iran and we hope this tool will improve access to information for people inside and outside the country.”

The company said that it was working to provide Farsi translations for the other 40 languages in the service.

Facebook hastily launched a Farsi version of its website. The website had appealed to its Farsi-speaking users around the world to help.

A Facebook spokesman said: “We could not have made this happen so quickly without the more than 400 Persian speakers who submitted thousands of individual translations of the site.”

Despite attempts by the authorities to control and restrict the flow of information from Iran, those angry at the disputed election results have been finding ways around the virtual barriers. Until now, Twitter and YouTube have been central in the protesters’ efforts to communicate with each other and with the wider world.

Tweets — messages sent through Twitter — have been used to organise the time and place of protests. At the request of the US State Department, Twitter delayed shutting down the site for maintenance earlier in the week to ensure that Iranians could continue to use the service.

YouTube, the video-sharing website, appears to have been blocked by Iran’s censors. Google, which runs the site, reported that traffic from within Iran to the site was down by 90 per cent since the protests began.

However, this has not prevented thousands of videos pouring on to the site, showing skirmishes and the enormous scale of the protests. The videos have generated millions of views. It is believed that most of these videos have been e-mailed from Iran to people outside the country, who have then loaded them on to YouTube.

Early reports from Tehran after the announcement of the election results suggested that the authorities had tried to interfere with, or had disabled, access to many websites and had blocked SMS text messaging. But hackers are helping to keep channels of access on the web open and have taken down President Ahmadinejad’s website in an act of cyber-sabotage.

Iran is a computer-literate society, with an estimated 700,000 bloggers, making Farsi the second-most popular language on the web after English.

So effective have Iranians been in their use of the internet that the Revolutionary Guard warned that action would be taken against “deviant news sites”. The Iranian regime is blocking a number of dissident blogs and websites.

These includes the BBC, which said yesterday that it had increased the number of satellites carrying its BBC Persian television service for Farsi-speakers in Iran and neighbouring Afghanistan and Tajikistan.

The BBC said that it had taken the action to circumvent what it said was Iranian jamming of the signal for its Persian service. The corporation said that there was “persistent interference” with a key satellite that was carrying the BBC’s international television and radio services in various languages, as well as similar services from other broadcasters. The BBC also said that it was extending the hours of its Persian TV and radio broadcasts.

“This is an important time for Iran, and many Iranians are turning to the BBC for impartial and independent news and information during this crisis,” said Peter Horrocks, director of the BBC’s World Service. “We also hope this will lessen the impact on other broadcasters who have been affected by the interference.”