Coimbatore Police Commissioner Sumit Sharan had on Friday said the city was under a high alert following information that the terrorists were heading there.
Police said on Saturday that vehicle-checks were intensified on arterial roads and highways connecting Coimbatore city with neighbouring states, and baggage thoroughly checked by armed police personnel.
Similarly checks were on in railway stations, bus-stands and the airport, they said.
The Tamil Nadu commando force carried out a flag march at Mettupalayam, about 35 km from Coimbatore, to instil confidence in people about security.
Armed forces were deployed at temples, mosques and churches, which were normally targeted by terrorists as was done in Sri Lanka recently, police sources said.
Kerala DGP Loknath Behera had on Friday also directed district police chiefs to keep utmost vigil across the state.