A prominent city shopping mall, an educational institution and a suburban railway station received bomb threat calls, prompting security officials to launch full-scale search of the respective premises, police said.
However, all these calls turned out to be hoax, City Police Commissioner J K Tripathy said.
Strongly condemning such rumours, he warned of strict action against anybody spreading such falsehoods.
Meanwhile, police were on the lookout for those who had made the hoax bomb threat calls.
A 24-year-old techie from Andhra Pradesh was killed and 14 persons were injured in twin blasts in two coaches of the Bangalore-Guwahati Express last night.