VIENNA – Vienna is a fabled city for spying – and now its cloak-and-dagger legend has a 21st-century twist.

A stately villa in a leafy district of the Austrian capital is at the center of a ruckus over whether the NSA is snooping on the city’s residents, with allegations flying that the building serves as a sophisticated U.S. intelligence listening post.

Both the U.S. and Austrian governments deny reports claiming to expose a major surveillance operation by the National Security Agency from within the towers of the sprawling manor. The U.S. Embassy says the building is an “Open Source Center” evaluating information freely available in newspapers and on the Internet.

With passions high over the NSA, Austrians question the need for any kind of U.S. intelligence gathering in their capital, including open source centers.

“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 more than 200 people.

Austria’s Kurier newspaper reported last 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 to comment.