PUEBLO VIEJO, Guatemala (Reuters) -- Hundreds of Maya Indians have seized control of Guatemala's largest dam and warned Wednesday they would cut power supplies if they are not compensated for land and lives lost in massacres when it was built.

Around 500 Mayan farmers, many of whom were survivors of brutal army massacres when the Chixoy hydroelectric dam was constructed more than 20 years ago, stormed the remote facility Tuesday.

The protesters also oppose government plans to build new hydroelectric projects across the country.

"No new dams can be built until they right the wrongs done to the people of Chixoy," protest leader Juan de Dios told Reuters. He said the protestors would shut off the dam's main turbines unless the government met with community leaders.

He denied reports on local radio that hundreds of armed men were supporting them, and said the action was peaceful. Reporters saw no signs that the protesters were armed.

Chixoy produces 275 megawatts of energy, accounting for 60 percent of Guatemala's electricity.

Located deep in the Mayan highlands, the dam has been controversial ever since development plans were first drawn up in the midst of bitter army repression during Guatemala's 36-year civil war.

In 1980, the army and paramilitaries killed 300 people from the village of Rio Negro, upstream from the proposed dam, after they refused a relocation offer.

Mainly women and children died during three massacres, where survivors say soldiers and paramilitaries raped women and broke open children's heads on rocks.

"They killed my mother, my sisters, my nieces and my wife and son, and when I finally agreed to be relocated the army took me to their base for eight days and beat me," said 42-year-old Francisco Chen.

Rio Negro survivors said they are also seeking compensation from the World Bank, which helped fund the dam's construction along with the Inter American Development Bank and continued to issue loans even after the atrocities.

Because of a series of technical blunders, including building on an earthquake prone fault line, the dam cost $1 billion -- $700 million over budget.

After an internal review, the World Bank concluded the massacres had taken place.

Other communities say they were never fully compensated for rich farming land flooded when the dam was built.

"I lost orchards and cattle, I was richer then. What little they gave us in return is just stones," said Juan Alvarez, 72, as he stood overlooking the vast dam.

Luis Ortiz, head of Guatemala's electricity board Inde said the protesters' demands were unjustified.

Last month, Guatemala announced plans to build several large new dams, including two on the Chixoy river, one with 330 megawatt capacity.

Copyright 2004 Reuters.