"Whatever it is, it's confirmation of intelligence agency activity in Vienna," said activist Rudolf Fussi, whose recently organized demonstration in front of the building drew over 200 people.
He said the government is guilty of cooperating with a foreign intelligence service, a crime punishable by a prison term, by allowing such activities and protecting the building with police.
Austria's Kurier newspaper reported this week that the U.S. government had decided to end operations at the site within a year or two and suggested that was because its cover was blown. CIA spokesman Edward Price refused comment in an email to The Associated Press Thursday.
Meanwhile, the allegations have turned into an Austrian affair of state.
Green party member Peter Pilz says Austria's National Security Council will convene in the next few weeks to discuss what went on inside the building after opposition parties and even some government coalition members called for such a meeting.
The affair is also straining the government coalition, comprised of center-right and center-left forces. The conservative-run Interior Ministry denies cooperation with the NSA and suggests that if there is any such collaboration it must come from the Defense Ministry, run by the rival party.
Defense Minister Gerhard Klug has yet to comment on the allegations. But Pilz, who sits on Parliament's security and intelligence committee, asserts that intelligence services run by both ministries work with and protect the NSA.
The villa is "clearly a U.S. intelligence center and according to our information NSA," he says, citing unnamed Austrian government officials as his source.