A German artist has projected the message "United Stasi of America" onto the US embassy in Berlin, likening reported sweeping Internet surveillance by Washington to spying by the former East German secret police.
A US embassy spokesperson told AFP: "Very funny. But anyone making such a comparison knows neither the Stasi nor the United States."
The reference to the former communist Staatssicherheit or Stasi police was beamed at night onto the US mission by German artist Oliver Bienkowski, in collaboration with Internet tycoon and online activist Kim Dotcom.
"I defaced the U.S. embassy in Berlin with a truth-projection last night. 0wned!" tweeted New Zealand-based Dotcom.
Dotcom, a German national, is the founder of file-sharing website Megaupload that was shut down by US authorities who seek to extradite him on charges of racketeering, fraud, money laundering and copyright theft.
Dotcom, born Kim Schmitz, denies any wrongdoing and is free on bail in New Zealand ahead of his extradition hearing.
US intelligence leaker Edward Snowden, in limbo at a Moscow airport, is also seeking to evade US justice after leaking explosive details about a vast US electronic surveillance programme and bugging of European missions.
Germany has reacted with particular alarm to the revelations about the US and British spy programmes, given its history of state surveillance under the Nazis and the communist East German regime.
A video that shows the protest message and a picture of Kim Dotcom beamed onto the US embassy on the night of Sunday to Monday has been posted online at http://www.youtube.com/watch?v=A2Yb3gWmm2I&feature=youtu.be.
It has already garnered more than 42,000 hits on YouTube.