Indian authorities said on Tuesday that charges have been slapped on four non-profit groups accused of fuelling protests against plans to build two atomic power stations, reports said.

The Press Trust of India, quoting Home Secretary R.K. Singh, said the four non-government organisations allegedly diverted foreign aid to fund protests against a nuclear power plant being built in southern Tamil Nadu state.

The online edition of The Hindu newspaper also quoted Singh as saying "cases have been registered against four NGOs for violation of Foreign Contribution Regulation Act".

It said the criminal charges were registered by the Tamil Nadu police as well as by a national police agency.

The NGOs were not named.

India on the weekend said it had frozen the assets of three non-government organisations on charges that they were drawing funds from the United States and Scandinavian countries and using them for anti-nuclear protests.

The country's move to build two atomic power stations in Tamil Nadu and another in the western state of Maharashtra has been thrown into disarray following the protests by villagers and activists.

The groups have denied the government's allegations.

In an interview published last week, Prime Minister Manmohan Singh blamed US non-profit groups for whipping up anti-nuclear demonstrations that have stalled the two new nuclear plants.

"The atomic energy programme has got into difficulties because these NGOs, mostly I think based in the United States, don't appreciate the need for our country to increase the energy supply," he told Science magazine.

India's fast-growing economy is dependent on coal, but Delhi hopes to raise the proportion of power produced from nuclear sources from less than three percent to 25 percent by 2050.