A group of about 300 Mazahua Indians briefly seized a water treatment plant on Mexico City's western outskirts and temporarily cut off one of the main sources of water for this metropolis of 18 million people on Wednesday.

The protesters live in the watershed of the Cutzamala River, which provides almost one-third of the city's water; they reportedly broke into the treatment plant late Tuesday, and closed the intake valves on Wednesday for about four hours.

The National Water Commission said in a press statement that full service would be restored by the end of Wednesday.

In September 2004, the same group staged a similar protest, blocking chlorine deliveries that placed at risk but did not stop the water supply. They were demanding damage payments for reservoir overflows that damaged crops, as well as money for rural development projects and drinking water systems for their own communities.

In late 2004, the government gave them almost US$120,000 in damage payments, promised to build water systems for them and gave them grants for thousands of Christmas tree seedlings to plant for cash income. The Mazahuas live in the high, pine-covered mountains west of Mexico City.

However, Wednesday's protest was motivated by demands for further government development aid.