Police on Tuesday lathicharged hundreds of people at the State border town of Gudalur when they forcibly tried to enter Kerala, demanding adequate protection to the 116-year-old Mullaperiyar Dam, over which both Tamil Nadu and Kerala are locked in a row.

Police said the crowd pelted stones at them and tried to force their way past a security cordon and go across to Kerala, prompting them to use batons.

In a similar action yesterday, police had lathicharged more than 4,000 protesters from 25 villages, who tried to forcibly enter Kerala, demanding increase in the dam level from 136 feet to 142 feet as per orders of the Supreme Court.

Police also expressed concern about reported movement of some suspected extremists on the Kerala side in Kumili and other areas and said they had alerted their counterparts in that State.

Meanwhile, local shop owners and people said they would not provide food and water to police for “working against their interests.”

The Mullaperiyar Dam row has sparked tension between Tamil Nadu and Kerala over building a new dam in place of the existing one. Kerala insists a new dam is the only solution, but Tamil Nadu maintains it is as good and safe as a new one.