Indian Defense Minister A.K. Antony's office has been bugged, and the authorities staged an immediate probe into the matter, highly placed sources said.

"The bugging came to light in the middle of February when two Indian Army personnel noticed interception of telephone lines of Antony's office. Subsequently, Defense Secretary Shashikant Sharma has asked the Intelligence Bureau to conduct a probe into the matter," the sources told the media.

Last year, snoopping devices were found in the office of Finance Minister Pranab Mukherjee.

The spying came to media after Mukherjee had written wrote to Indian Prime Minister Manmohan Singh about adhesive-like substance recovered from his office that might have been used to implant electronic listening devices.