WASHINGTON — The Obama administration says it has tried to avoid words or deeds that could be portrayed as American meddling in Iran’s presidential election and its tumultuous aftermath.

Yet on Monday afternoon, a State Department official e-mailed the social-networking site Twitter with an unusual request: delay scheduled maintenance of its global network, which would have cut off service while Iranians were using Twitter to swap information and inform the outside world about the mushrooming protests around Tehran.

The request, made to a Twitter co-founder, Jack Dorsey, is yet another new-media milestone: the recognition by the United States government that an Internet blogging service that did not exist four years ago has the potential to change history in an ancient Islamic country.

“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?’ ” said P. J. Crowley, the Assistant Secretary of State for Public Affairs.

Twitter complied with the request, saying in a blog post on Monday that it put off the upgrade until late Tuesday afternoon — 1:30 a.m. Wednesday in Tehran — because its partners recognized “the role Twitter is currently playing as an important communication tool in Iran.” The network was working normally again by Tuesday evening.

The State Department said its request did not amount to meddling. They noted that they did not contact Twitter until three days after the vote was held and well after the protests had begun.

“This is completely consistent with our national policy,” Mr. Crowley said. “We are proponents of freedom of expression. Information should be used as a way to promote freedom of expression.”

The episode demonstrates the extent to which the administration views social networking as a new arrow in its diplomatic quiver. Secretary of State Hillary Rodham Clinton talks regularly about the power of e-diplomacy, particularly in places where the mass media are repressed.

The State Department’s Policy Planning Staff, has been working with Twitter, YouTube, Facebook and other services to harness their reach for diplomatic initiatives in Iraq and elsewhere.

Last month, they organized a visit to Baghdad by Mr. Dorsey and other executives from Silicon Valley and New York’s equivalent, Silicon Alley. They met with Iraq’s deputy prime minister to discuss how to rebuild the country’s information network and to sell the virtues of Twitter.

Referring to Mir Hussein Mousavi, the main Iranian opposition candidate, Mr. Crowley said, “We watched closely how Mousavi has used Facebook to keep his supporters informed of his activities.”

Tehran has been buzzing with tweets, the posts of Twitter subscribers, sharing news on rallies, police crackdowns on protesters, and analysis of how the White House is responding to the drama.

With the authorities blocking text-messaging on cell phones, Twitter has become a handy alternative for information hungry Iranians. While Iran has also tried to block Twitter posts, Iranians are skilled at using proxy sites or other methods to circumvent the official barriers.

A Twitter account called IranNewsNow sent a message to CNN’s Twitter account that read, “don’t listen to what iran gov says u can or can’t do! You can report the pics/vids coming from Twitter!”

An account called StopAhmadi wrote on Tuesday evening, “We need ppl around world helping to raise the issues put pressure on Iranian gvmt.” It posted links to pictures from Tehran, including one that showed a man bleeding profusely from his chest, surrounded by protesters.

There were also suspicions that some pro-government forces might be using new-media outlets to send out misinformation. One popular opposition site, Persiankiwi, warned its followers on Tuesday to ignore instructions from people with no record of reliable posts.

In addition to Twitter, YouTube has been a critical tool to spread videos from Iran when traditional media outlets have had difficulty filming the protests or the ensuing crackdown. One YouTube account, bearing the user name “wwwiranbefreecom,” showed disturbing images of police officers beating people in the streets. On Monday, Lara Setrakian, an ABC News journalist, put out a call for video on Twitter, writing, “Please send footage we can’t reach!”

The BBC’s Persian-language television channel said that for a time on Tuesday, it was receiving about five videos a minute from amateurs, even though the channel is largely blocked within Iran. One showed pro-government militia members firing weapons at a rally.

“We’ve been struck by the amount of video and eyewitness testimony,” said Jon Williams, the BBC world news editor. “The days when regimes could control the flow of information are over.”

As new media proliferate, however, traditional journalists are having a harder and harder time.

Journalists were told on Tuesday that they could not cover protests without permission. The restrictions “effectively confine journalists to their offices,” a spokesman for the BBC said.

Still, many ventured out into the streets to witness pro and anti government protests, at considerable risk.

At the Laleh Hotel in central Tehran, the Time magazine columnist Joe Klein said, “A number of journalists were coming back from the streets pretty badly beaten.”

As their visas expired, journalists were looking for any chance to report.

Jim Marshall, the last Sky News staff member in Tehran, was barred from reporting, so he went shopping instead and came upon thousands of supporters of President Mahmoud Ahmadinejad at a rally.

“I kept shopping, and they kept demonstrating,” he wrote in a blog post. “This was turning into a test of wills. How much longer could I shop without slipping into reporting?” Once he realized he was carrying a notepad in his pocket, he swiftly left the scene.