An anonymous call on Saturday claiming that a bomb was planted in the high-security Vidhan Soudha, the state secretariat in Bangalore, turned out to be a hoax, police said.
Police swung into action, deploying sniffer dogs to search the premises in the heart of the city, but found no explosives.
The caller, who used his mobile phone to contact the police control room, had been identified and a search was on for him, police said.
After the arrest of two Pakistani militants in Mysore recently, the city police have tightened the security around the assembly complex allegedly targeted by terrorists.
The offices in Vidhan Soudha and its annexe were closed on account of being a second Saturday.