Stepping up their protest against the atomic power plant here, anti-nuclear activists on Thursday stood in sea waters forming a human chain off nearby Indinthakarai coast.

Taking a leaf from 'Jal Satyagraha' activists in Madhya Pradesh, the activists of People's Movement Against Nuclear Energy (PMANE) stood in the waters close to the shores in a new turn to their year-long protests.

Police, whose presence has been strengthened in and around the sea shores with additional forces, have beefed up security along the coast to prevent any untoward incident during the day-long protest.

The agitators have put forward four demands - stoppage of the process of fuel loading in Kudankulam Nuclear Power Project, drop the plan to arrest anti-nuclear movement leaders, adequate compensation for those who suffered losses and release of those already taken into custody.

The new form of protest came even the whereabouts of PMANE leader S P Udayakumar remained unknown after he did somersault on his offer to surrender before police after the protest turned violent that led to police firing claiming the life of one fisherman in Tuticorin district on Monday.

The current bout of intensified protests, including the failed bid to lay siege to the plant, was launched by PMANE to prevent loading of fuel for which regulatory authorities gave the approval recently.

On September 10, the Madhya Pradesh government had agreed to the main demands of protesters who undertook a 'Jal Satyagraha' in Khandwa district, saying they would be given land as compensation and height of Omkareshwar Dam would be reduced.

The entire Kudankulam town had almost been sealed by police since yesterday with the personnel taking positions at strategic places, especially around the KNPP where the preparations for loading of enriched uranium are underway.

Police said they conducted a house-to-house search for PMANE activists, wanted in connection with Monday's incidents, in the Tsunami village near here last night.