Indian food festivals are to be held in the country’s north-eastern states of Tamil Nadu, Karnataka and Kerala, amid fears that a “terrorist attack” is being planned.
On Sunday, police said a suicide bomber had attacked a police station in the state capital, Chennai, and a “large number of police personnel” were wounded.
The attack happened at about 10.30am (0030 GMT), according to the State Crime Records Bureau, and there was no immediate claim of responsibility.
According to police, the blast was not linked to any specific group or group of people.
“There are reports of a small bomb explosion, but no one has been arrested yet,” said a senior police officer, adding that investigations were ongoing.
Indian media reported that the suicide bomber blew himself up at a police checkpoint near the station.
The bomb, which was not explosive, had reportedly been hidden in a small bag at the scene, but it was not immediately clear how it was made.
The police station is located at a junction of two major roads, one in Chennai and the other in Bangalore.
The main traffic route runs through the area.
The suicide bomber was carrying a small explosive device.
A senior police official said the suicide attack was not connected to any particular group or organisation.
“We are trying to find the person who is responsible,” said police officer G.P. Chatterjee, adding he could not say whether the attack was connected to an ongoing terrorist threat.
In April last year, three men blew themselves up outside a hotel in the city of Coimbatore, killing nine people and injuring dozens.
The incident sparked a national debate over intolerance and violence in India.
Police said that an initial investigation showed that the incident was a suicide attack.
Police have since recovered the bomb and arrested three men.