VILLAHERMOSA, Mexico (Reuters) - A huge mudslide engulfed a remote village in flood-ravaged southern Mexico on Monday and the government said at least 16 people were missing.

Mexican media gave a higher toll, saying the landslide in southern Chiapas state buried some 100 houses in the community of San Juan Grijalva and as many as 30 people could be missing.

"A mountain fell into the river, blocking the River Grijalva ... and created a wave ... that has flattened the town of Juan de Grijalva," Chiapas Gov. Juan Sabines told Mexican radio.

TV images showed a swathe of tropical jungle swamped by water and mud, and bare earth where houses once stood.

Interior Minister Francisco Ramirez Acuna telephoned President Felipe Calderon to alert him about the mudslide. Rescue workers helicoptered to the scene to evacuate survivors.

Civil protection authorities in Chiapas, a mostly indigenous state where floods already killed four people last week, said they were still trying to confirm casualties.

"We know there was a mudslide there but we don't know its magnitude," said civil protection official Alejandro Cabrera. "We are trying to re-establish communication."

San Juan Grijalva is close to Tabasco state, which is mostly under water after last week's rain caused rivers to burst their banks and left some 800,000 people homeless.

In Tabasco's devastated capital, Villahermosa, residents drank from a muddy river and cisterns in their homes as water and food became scarce.

"For lack of water, they're taking it out of cisterns and the river," Janette Aguilera, 32, said of her neighbors.

In an interview with Mexican radio, Tabasco state Gov. Andres Granier said it would be months before all Villahermosa's evacuated residents could return.

"We're calculating the problem as one of three months ... before 100 percent of the people can go home," he said.

The land around the city, where bananas, beans and corn are grown, was devastated. "The countryside is totally lost," Granier said.

INTERNATIONAL AID

Thousands of people have been plucked from rooftops by helicopter or rescued by boat. Large parts of Tabasco resembled a huge lake with just the tops of roofs poking through.

Only one death has been reported in Tabasco, although in the neighboring state of Chiapas, local government officials reported four fatalities on Sunday after rain-swollen rivers burst their banks, damaging thousands of homes and 16 bridges.

Aid was getting through. Volunteer workers piled plastic bags full of beans, cooking oil and rice onto a launch with an outboard motor that headed off down a flooded street.

Cuba will send a plane with 50 doctors to treat Tabasco residents, Granier said. The United States is donating $300,000 to the affected area.

Looting continued and 53 people were arrested in Tabasco, a state prosecution official said.

Housewife Susana Clemente Torres, 45, said, "I went to see my house and I found two people robbing it."

As a gesture of goodwill, President Felipe Calderon, who has visited Tabasco several times in the last few days, said he might pardon the debts of tens of thousands of Tabasco residents who have not paid electricity bills for years in a political protest dating back to the mid-1990s.

The low-lying state produces some oil but there have been no reports of output losses.

(Additional reporting by Luis Manuel Lopez, Catherine Bremer and Miguel Angel Gutierrez; Editing by Eric Beech)