Authorities said two more bodies were found floating in brackish waters covering much of Mexico's southern Gulf coast, as residents began running perilously short of food and water after a week of devastating floods. The Interior Department said the cause of death of the two people found Sunday was under investigation. If confirmed caused by the flooding, the disaster's toll would stand at 10. "We are seeing one of the worst natural catastrophes in the history of the country," President Felipe Calderon said Sunday in Tabasco state. "Not only because of the size of the area affected, but because of the number of people affected." Since rivers first began to burst their banks October 28, the flooding has destroyed or damaged the homes of as many as half a million people, and at least that many more have been affected by severed utilities and transportation corridors, according to government estimates. In neighboring Chiapas state, four bridges and 180 miles (300 kilometers) of roads were washed out. "People are fighting over food and water, and the lack of electricity and running water are making life in the city impossible," said Martha Lilia Lopez, who has been handing out food to victims on behalf of a nonprofit foundation she heads. Many in Tabasco remained camped out on the rooftops or upper floors of their flooded homes to guard their possessions from looters, but their resolve was running out - along with water, food and other supplies. "I would prefer to be in my house instead of a shelter, but we ran out of everything," said Patricio Bernal, 53, who was evacuated by boat along with his wife from their home in the state capital, Villahermosa. "We spent days without food. We thought we were going to die," said Marta Vidal, 47, who was taken to safety by helicopter. Daniel Montiel Ortiz, who oversaw helicopter rescue efforts for the federal police, said rescuers were now focused on "selective evacuations" - primarily of sick people - and delivering badly needed supplies to isolated communities still surrounded by water. Some desperate residents in Villahermosa broke into shuttered stores and took food and household goods, and police reported detaining about 50 people for looting over the last couple of days. But Ortiz called those "isolated incidents." After water covered about 80 percent of Tabasco's already swampy coastal territory, authorities struggled to calculate the damages. The federal Social Development Department estimated that the homes of 400,000 to 500,000 people were damaged or destroyed. River levels began to recede slightly Sunday, but Villahermosa remained largely flooded. Health authorities reported cases of eye, skin, intestinal and respiratory infections, but no mass outbreak of waterborne diseases that many had feared.