With security tightened in the wake of the Hyderabad blasts, more than 700 "suspicious elements" have been arrested in the city, a top police officer said.
Chennai Police Commissioner G Nanchil Kumaran, after a security review with high-ranking police officers in Chennai on Sunday, told reporters that strategic locations like the Central station and Secretariat have been brought under heightened surveillance.
"Intensified night vigil and patrolling since last night have resulted in the arrest of 720 suspicious persons who are being questioned," he said.
He also said 53 check-posts have been installed in and around the city and all vehicles entering Chennai are allowed only after thorough checking.
Further, people are requested not to touch unidentified parcels and objects and should immediately report such incidents, police said.