Thousands perched on rooftops in Mexico floods

VILLAHERMOSA, Mexico (Reuters) - Thousands of people perched on roofs in southern Mexico on Saturday, desperate to be evacuated from flooding caused by heavy rains that has left most of Tabasco state under water and 800,000 people homeless.

Many were set to spend another night on their rooftops, with tens of thousands already crammed into emergency shelters struggling to provide enough hot meals and dry beds.

One group stranded on a roof held a banner reading: "Enough. There are children, pregnant women, sick women. Send the police."

"We need help," one woman told Reuters Television after being rescued by helicopter from the roof of a school in the swampy southern Gulf of Mexico state.

"There are a lot of people up there, there are pregnant women, children. They didn't want to leave their homes but there's now no other option. We've lost everything," she said.

Local navy commander Sergio Lara said 28,000 people had been evacuated as army and navy teams worked through Saturday to airlift people out or reach them by boat, despite problems with fog and rain and with flood victims trying to grab onto hovering helicopters.

"What can complicate things is the weather. (And) today a helicopter almost fell down because of the people desperate to reach provisions," said Jorge Camacho, a civil protection director from the northern state of Nuevo Leon.

Only one death has been reported in Tabasco so far. But in the largely impoverished southern state of Chiapas, local media said four people had died after rain-swollen rivers burst their banks, damaging 5,000 homes and 16 bridges.

FOOD, WATER RUNNING OUT

In Tabasco, tempers ran short as people searched for family members and fought over dwindling food and drinking water supplies. A supermarket in the state capital Villahermosa was looted as many stores ran out of stocks.

With electricity and drinking water cut off in much of the state, and fixed-line and cellular telephone networks down, several thousand Tabascans fled on buses on Friday to the neighboring states of Veracruz and Campeche.

Authorities said on Saturday they had started restoring drinking water to parts of the state.

Tabasco Gov. Andres Granier, who opened up his government offices as a refuge, said river levels were going down slightly despite more rain overnight that left floodwaters moving swiftly.

People and livestock swam through streets in neck-high, murky brown water on Friday after floodwaters burst through sandbag barriers into Villahermosa, home to about half a million people.

The Grijalva River that winds through the city swelled over its banks earlier in the week after days of heavy rains that triggered some of the worst flooding the low-lying region has seen in half a century.

President Felipe Calderon called the situation critical as flood levels reached 19 feet in some areas, and food supplies were trucked in from across the country.

The storms also disrupted Mexico's oil shipments to the United States for most of the week, although state energy monopoly Pemex reported no impact on its oil wells in Tabasco.

Granier said more than 1 million people, about half of the state's population, were affected by the flooding. On Saturday he imposed a temporary ban on alcohol sales in parts of the state because of the disaster.