A web-based U.S. "embassy" to Iran has been blocked by Tehran less than a day after it went online, residents said Wednesday.

The English- and Farsi-language website, designed by Washington as a virtual diplomatic mission, had been briefly available to Internet users in Tehran after its Tuesday debut. It could not be accessed on Wednesday.

Iranian Internet users trying to view the site said they were greeted by a message stating that their browser could not display it, or by a page provided by Iranian authorities that suggested links to local websites instead.

Numerous websites, including international media and social networking sites, are unavailable in Iran.

Calls to Iranian officials for comment were not immediately returned.

In Washington, State Department spokesman Mark Toner said Iranians were still reaching the virtual embassy's page through private networks. U.S. officials are confident they will be able to work around Iran's block to make the site available for everyone else again, he said.

Iran's interference with a site providing information about U.S. policies and travel to the United States "speaks volumes about their trust in their own citizens," Toner told reporters. He decried the Iranian efforts to close citizens off from the outside world.