Coimbatore: Security has been tightened at all public places in the city after an anonymous caller rang up the police control room and warned of blasts at seven areas and dared them to try and prevent it.

Police said the caller rang up this morning and said there would be blasts at seven places and to try and prevent them. But when asked to elaborate, he said it was not important and what was crucial was that the explosions would take place, especially in Ganapati area. On getting this information, Police Commissioner A K Vishwanathan ordered the force to be on full alert and deployed additional force at places with large public concentration, including bus stands, railway stations, airport, places of worship and malls and markets, they said.