Intel reports say one of the six is believed to be a Pakistani national while the rest are Sri Lankan Tamil. The report noted that the men were disguised as Hindus.
The intel report suggests terrorists could target vital security installations and worship centres, tourist locations and foreign embassies in the region. The 14 major road routes that lead to the southern Indian city of Coimbatore are under heightened security measures.
The city police have deployed over 2,000 plainclothes and uniformed law enforcement officers to prevent incidents and catch the terrorists.
Tamil Nadu has been on the radar of terrorists for the past few months, and the country's National Investigation Agency (NIA) has arrested at least ten men, from across the state, suspected to have links to the banned terrorist organisation Daesh (Islamic State). Investigators allege they had plans to launch terror attacks in the state.
One of those arrested was Mohammed Azharudheen, 32, the alleged head of a suspected Daesh branch in Tamil Nadu, said to be a contact of Zahran Hashim, the alleged ringleader in the 21 April, Easter Sunday bombings that targeted Sri Lankan churches and hotels, leaving 253 people dead and over 500 injured.