The Obama administration, while insisting it is not meddling in Iran, yesterday confirmed it had asked Twitter to remain open to help anti-government protesters.

The company had planned a temporary shutdown to overhaul its service in the middle of the night on Monday but the US state department put in a request to postpone this.

Many protesters have being using Twitter to spread information about rallies and to share news.

White House spokesman Robert Gibbs, asked about this at a press conference yesterday, would neither confirm or deny it, saying only that a free press and a means of communication were important.

But the state department yesterday confirmed a request was made to Twitter.

The New York Times last night identified the author of the request as Jared Cohen, a 27-year-old state department official. Twitter complied with the request, delaying its overhaul until last night.

PJ Crowley, the assistant secretary of state for public affairs, told the New York Times: "This was just a call to say: 'It appears Twitter is playing an important role at a crucial time in Iran. Could you keep it going?'"

Obama has adopted a cautious approach to Iran, not wanting to be accused of interfering in its elections for fear of derailing hoped-for direct negotiations with Tehran over its alleged nuclear weapons programme.

Crowley said the request to Twitter did not diverge from Obama's policy. "We are proponents of freedom of expression. Information should be used as a way to promote freedom of expression."