A secret listening device found at the Geneva offices of the United Nations (search) was in a room adjoining a main conference hall, where it could have been used to eavesdrop on any private conversations, the global body said Friday.

Secretary of State Colin Powell (search) and other foreign ministers of the U.N. Security Council discussed the situation postwar Iraq in the main hall last year. It was not immediately clear who used the smaller room.

The eavesdropping equipment could be Russian or East European in origin and was made three to four years ago, one expert told Swiss television.

Workers found the device during renovation work this fall on the room, known as the Salon Francais, or French Lounge, said Marie Heuze, spokeswoman for the U.N. office in Geneva.

"I can confirm that in the course of the renovation of the Salon Francais workmen found what is considered to be a sophisticated listening device," Heuze told reporters.

"An investigation failed to determine who planted the device," Heuze said. "I am not authorized to say anything else."

The art deco room in the United Nations' European headquarters adjoins the Salle de Conseil, or Council Chamber, which was used for a meeting of Powell and other foreign ministers of the permanent members of the U.N. Security Council in September 2003.

Officials said they were unsure whether the room with the listening device had been used by any of the ministers.

The device could have been in operation in the run-up to the U.S.-led invasion of Iraq, judging from the age of the equipment.

The Salon Francais also is the venue for a weekly teleconference meeting between U.N. Secretary-General Kofi Annan (search) and the head of the Geneva office, Sergei Ordzhonikidze.

The U.N. offices in Geneva were originally used before World War II as headquarters of the League of Nations. The Salon Francais is so called because it was decorated in art deco style by French artist Jules Leleu in 1935.

"Never truly renovated since this date, the room was starting to suffer from the assault of time," the French mission to the U.N. Geneva office said in a newsletter dated Monday.

The room has no other connection with France, Heuze said.

"It's a very sophisticated piece of listening equipment where the sound is picked up and immediately retransmitted," Patrick Daniel Eugster, the head of Geneva-based Surveillance Consulting Group, told the French-language broadcaster Television Suisse Romande, or TSR.

TSR showed photographs of the listening device to Eugster, who said that transmissions from the device would be so short that they would be very difficult to pick up.

"We have a main transmitter with a small antenna," Eugster said, adding that the device was "very probably" made in Russia or Eastern Europe.

"There are two microphones. It was made about three or four years ago, because the different parts are quite big and the parts now on the market are a lot smaller."