Tension prevailed here for about five hours on Sunday as the police thwarted a bid by about 3,000 agitators to lay siege to the Kudankulam Nuclear Power Project (KKNPP) site to protest fuel-loading in the reactor.

Earlier in the day, the protesters, led by the People’s Movement Against Nuclear Energy convener, S.P. Udayakumar, surprised the police, who deployed about 4,000 personnel, marched towards the site through the shore around noon.