Rescue workers in southern Mexico have found two bodies while searching for at least 16 people reported missing after a landslide buried their village.
The village of San Juan Grijalva was devastated by the landslide
The mudslides in Chiapas state were caused by heavy rains, which have also flooded 80% of neighbouring Tabasco state, leaving 500,000 people homeless.
At least 10,000 people are still cut off by floodwaters and many people are still waiting for aid supplies.
The floods that hit last week are some of the worst in Mexico's history.
During a visit to the area, President Felipe Calderon pledged nearly $660m towards relief and reconstruction work.
"I know it is not enough, but it is a start," he said.
Residents in the village San Juan Grijalva in Chiapas reported hearing a loud rumbling noise on Sunday night as a hillside collapsed into the Grijalva river.
A wall of water, mud and rocks swept away houses, and pictures showed bare earth and tangled wreckage where the village once stood.
Local media reports said the landslide had buried many houses and as many as 30 people could be missing.
"This village practically disappeared," Chiapas Governor Juan Sabines was quoted by the Associated Press news agency as saying.
In Villahermosa, the capital of Tabasco state, floodwaters are continuing to recede, but thousands of people are still stranded and waiting for supplies to reach them.
The water has cut off roads, creating huge difficulties in distributing aid.
In the hard-hit state capital, Villahermosa, fights broke out over sparse supplies of aid.
About 50 people were reportedly arrested over isolated looting incidents during the weekend.
Tabasco state Governor Andres Granier said it would be several months before all the people evacuated from Villahermosa could return to the city.
Earlier in the crisis he said 100% of the state's crops, including bananas, corn and beans, had been destroyed.
"The countryside is totally lost," he said.
International help for the flood-stricken communities has begun to arrive alongside Mexican aid of helicopters, bottled water and water purification equipment.
Much of Villahermosa is still covered in water
Thousands of Mexicans have donated money to buy supplies.
"I thank the world's solidarity, Latin America, Europe, in helping us at this time," President Calderon said.
Donations have been pledged by countries including Ireland ($1.4m), the US ($300,000) and Germany ($250,000).
Peru is said to be sending a planeload of supplies, Britain 10 experts and inflatable boats, and Cuba 50 doctors.