The Tamil Nadu government has been alerted by Central intelligence agencies about a possible terror strike in Chennai, prompting authorities to beef up security in markets and crowded places.

Tamil Nadu Director General of Police on Monday told mediapersons that he had received a terror alert for the state. Nanjil Kumaran said market places and crowded areas in the city were given security cover.

Kumaran said the Intelligence Bureau (IB) had issued a general alert not only for Chennai but for all states about "certain designs by certain terrorist elements based abroad trying to do some kind of an action that they can take up in India".

A home ministry official in New Delhi said the state governments have been asked to beef up security at religious and crowded places in view of  Janmashtami and Ganesh Chaturthi festivals later this month.

Mathura, the birthplace of Lord Krishna, is under a tight police cover for the festivities as lakhs of devotees are expected to converge in the temple town.