MEXICO CITY - One person was killed and more than a million people affected by flooding in Mexico's southern state of Tabasco, officials said, as hundreds of thousands Friday waited for rescuers to pull them out of their homes in the worst floods ever in the region.

The oil-rich state the size of Belgium is now 80 percent underwater, officials said, adding that they expect more rain in the next days.

©Gilberto Villasana/AFP/Getty Images
General view of a flooded area in the city of Villahermosa, Tabasco state, Mexico on November 1, 2007. More than 700.000 people were affected by the heavy rain --unrelated to Hurricane Noel-- in the state of Tabasco.

Area rivers continue to swell due to the non-stop rain, and more than 850 towns have been flooded in the Gulf of Mexico state, officials said.

"Of the 2.1 million Tabasquenos, more than half are suffering from this serious problem that has not been experienced in the history of Tabasco," state Governor Andres Granier told reporters.

"New Orleans was small compared to this," said Granier, comparing his flooding to the flooding caused by 2005's Hurricane Katrina in the southern US city.

There is one major difference with Katrina: as of late Thursday only one person was reported killed by the flooding. That person died Wednesday.

"Around 300,000 people are still trapped in their homes in different locations," he said, adding that army and navy helicopters and rescue boats were working on the rescue effort.

"The situation is extraordinarily grave," said Mexican President Felipe Calderon, addressed the nation late Thursday asking for donations.

He described the situation as "one of the worst natural disasters in the history of the country."

Tabasco "is devastated," said Granier, governor of the 29,000 square kilometer (11,000 square mile) state. "100 percent of crops are lost."

Granier warned that the flooding could get even worse as forecasters say a new cold front could bring more rain over the weekend.

Some 400 doctors and health workers were deployed to more than 300 towns to detect any outbreak of infections, according to the state's Civil Protection agency.

State officials warned that non-stop rain would result in swollen rivers, one full week after the first flooding started.

The floods began last week when a cold front brought heavy rain that caused rivers to burst their banks.

Soldiers and state authorities had placed more than 700,000 sand bags along the rivers to prevent flooding, but the water rose above the barriers.

The floods worsened over the past three days as authorities drained water from two dams in the neighboring state of Chiapas to prevent them from exceeding their capacity. The drainage caused three Tabasco rivers to burst their banks.

The water rose again Thursday in the state capital of Villahermosa, which was flooded Wednesday after the Grijalva River burst its banks.

But hundreds of Villahermosa residents refused to leave their flooded homes amid reports of looting in the city of 750,000 people.

"There's no policing," a woman living in Villahermosa told reporters. "The thieves climb on the roofs and open the doors through there."

In the neighboring state of Chiapas, authorities declared a state of emergency in 22 municipalities while 2,500 people have been taken to shelters.

The Federal Electricity Commission also said it was unclear when it would be able to close the spigots in the Penitas dam in Chiapas.