US National Security Agency
America's National Security Agency (NSA) is a cryptologic intelligence agency of the United States Department of Defence responsible for the collection and analysis of foreign communications and foreign signals intelligence. The NSA is a key component of the US Intelligence community, which is headed by the Director of National Intelligence. By law, the NSA's intelligence gathering is limited to foreign communications although there have been some incidents involving domestic collection, including the NSA warrantless surveillance controversy.
Villa in Vienna suspected of being US spy base
Associated Press in 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 centre of a row over whether the US National Security Agency is snooping on the city's residents.
Allegations are flying that the building serves as a sophisticated US intelligence listening post.
Both the US and Austrian governments deny reports claiming to expose a major surveillance operation by the NSA from within the towers of the manor.
The US Embassy says the building is an "Open Source Centre" evaluating information freely available in newspapers and on the internet. Such centres are run by the CIA.
Despite the denials, many Austrians remain sceptical in a country shocked at revelations by former NSA contractor Edward Snowden that the organisation has been able to spy on the online activities of millions of people worldwide.
The Viennese are also mindful of the city's cold war reputation as the spying capital of the world - an outpost for eavesdropping by both sides of the divide. With passions running high over the NSA, Austrians question the need for any kind of US intelligence- gathering in their capital, including open source centres.
"Whatever it is, it's confirmation of intelligence agency activity in Vienna," said activist Rudolf Fussi, who recently organised a demonstration in front of the building which drew more than 200 people.
He said the Austrian government was guilty of co-operating 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 US 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. Meanwhile, the allegations have turned into an Austrian affair of state.
Green party member Peter Pilz said Austria's National Security Council would convene in the next few weeks to discuss what went on in the building after opposition parties - and even government coalition members - called for such a meeting.
The affair is also causing tensions within the government coalition, comprising centre-right and centre-left forces.
The conservative-run Interior Ministry denies co-operation with the NSA.
It suggests that if there is any such collaboration, it must come from the Defence Ministry, which is run by the rival party.
Defence Minister Gerhard Klug has yet to comment on the spying 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 was "clearly a US intelligence centre and according to our information [is run by the] NSA", he said, citing unnamed Austrian government officials as his source.