TEHRAN — Well, that didn’t last long.

Less than 12 hours after opening, the Obama administration’s “virtual embassy” in Iran was blocked by Tehran’s digital gatekeepers on Wednesday.

Instead of seeing a welcome message from Secretary of State Hillary Rodham Clinton, Iranians trying to reach the site were directed to an Iranian government Web page. It warned that visiting the American site was “against the law.”

White House spokesman Jay Carney condemned the blockage in a statement Wednesday evening, saying the Iranian government had “again demonstrated its commitment to build an electronic curtain of surveillance and censorship around its people.”

The Iranian government’s move to block the site nearly as soon as it was launched illustrates the problems the Obama administration faces as it tries to keep the resource available to all Iranians.

The State Department had said that it anticipated that Tehran would prevent access to the site, just as it does with millions of others sites -- among them, CNN, Gawker and Playboy.

Officials say they think they will be able to get the site back up.

That “the Iranian government would attempt to block access to a site that ... does nothing more other than offer information about how to travel to the United States and opportunities for travel to the United States, as well about our policies, in a very transparent and straightforward manner, speaks volumes about their trust in their own citizens and then -- and closing them off to the outside world,” said State Department spokesman Mark Toner.

Toner added that Iranians with “virtual private networks” — software that allows users to reach blocked content through portals in other countries — can still see the site. Some of the content from the site is also being read on social media sites such as Facebook, Toner said.

Based on early indications in Tehran, some Iranians with access to the site remain a bit underwhelmed.

“Why can’t we apply for visas at this embassy?” asked Sohrab, a nanotechnology student who declined to provide his full name. “Now it is more of a propaganda tool, telling us about U.S. culture — but we can see that on the satellite channels.”