Coimbatore: After intelligence inputs said six terrorists had entered Tamil Nadu on Thursday, a high alert was sounded in Coimbatore. The terrorists are suspected of entering the nation from northern Sri Lanka through Rameswaram in Tamil Nadu, claiming to have connections with the Lashkar-e-Taiba.  Currently, the 14 main roads leading to Coimbatore are under rigorous surveillance, while police forces with over 2000 duty staff, both in regular uniform and in casual clothes, have been deployed to cope with the current scenario.