The district administration has extended the prohibitory orders from 2 km to 5 km radius of the plant since this morning.
Besides, 11 companies of Tamil Nadu Special Police and Tamil Nadu Armed Police have been deployed, in addition to the existing force in the area.
The police action followed information that People's Movement Against Nuclear Energy, which is spearheading the protest against the nuclear plant, was planning to intensify its stir from tomorrow, since the state government did not respond to its demand for talks.
"It has been nine days now and the state government has not responded to our hunger-strike. So, we have called our supporters from five villages and would have a meeting to decide further course of action tomorrow," PMANE activist M Pushparayan said.
The activists' move comes against the backdrop of Tamil Nadu Chief Minister Jayalalithaa's assertion that the plant would go critical in the next 10 days and power generation would begin then.