The Swiss government has been accused of hiding surveillance systems in cuckoo clocks and then giving them as official gifts to at least 30 embassies.
The foreign ministry has yet to comment officially on the claims, made in United States diplomatic cables released last week by the WikiLeaks whistle-blowing website.
The alleged bugging came to light in cables sent in September 2006 from the US embassy in Bern to the US State Department.
In it, an unnamed official expressed security concerns about the cuckoo clock – a pendulum-driven “Chalet” model with music box – which had been presented to the ambassador the previous month as part of Swiss National Day celebrations.
“The latest addition to the living room is proving to be a good conversation piece, but I’m not sure we should be holding conversations around it,” the official wrote on September 14.
“The bird came out at midnight yesterday and I swear something flashed.”