Six days of rain turned rivers into angry torrents that tore across the southern Mexico state of Chiapas, sweeping away houses, bridges and big trees. At least 25 people drowned and as many were reported missing and feared dead.

Another seven died in flash flooding in other southern Mexico states after heavy rains pounded the region.Chiapas Gov. Roberto Albores Guillen declared a disaster zone along the Pacific coast Tuesday. He said at least 25,000 people in more than 50 towns and villages were driven from their houses by rampaging rivers and creeks.

President Ernesto Zedillo ordered 1,100 army troops and two 727 jets loaded with doctors, medical equipment and specialized personnel to Chiapas.

However, bad weather made it impossible to get aid by airplane to some isolated towns, where dozens of people were stranded on rooftops and islands surrounded by raging currents, the Televisa television network reported.

The mayor of one of the most affected areas - the town of Pijijiapan, Chiapas - said rescuers had pulled 18 bodies from the waters in his town alone.

"The water is rising," the mayor, Gilberto de los Santos Cruz, said in a telephone interview.