On a map, this cluster of tin-roofed mountain houses lies less than 100 miles northeast of Mexico City, but by road it is eight hours and a world away, in Mexico's remote south-central mountains. And for the last 10 days, it has been unreachable--severed from the outside by sliding mud.

Today, nearly three dozen of its residents raced down hillsides and across ravines to greet the first sign of help--a Mexican air force Mi-8 helicopter that arrived with more than a ton of beans, rice and oil for this hungry community of several hundred people.

Tlaxco Puebla is one of the fortunate villages in this storm-ravaged region. Across the flooded hollows and remote mountain ridges of Puebla state, where more than two-thirds of the country's weather-related deaths have occurred in the last week, government officials and volunteers are using helicopters, mules and foot brigades to supply hundreds of communities that have been cut off by the most damaging rains here in decades. The areas of devastation are so vast and transport problems so great that officials concede they still have been unable to reach dozens of communities.

"We're using helicopters as the temporary solution," said Rafael Moreno Valle Rosas, Puebla's finance minister, who was dispatched to coordinate relief efforts in one of the hardest-hit mountain regions. "But even [helicopters] can't land in some areas."

According to official tallies, 329 people have been killed by landslides and flooding over the past 10 days in Mexico's southern states, 237 in Puebla, while several nongovernmental agencies say the toll could exceed 600. Nationwide, nearly 300,000 people have been driven from their homes by storms that have turned cities into rivers and sent neighborhoods sliding off water-saturated mountainsides.

Even as soldiers and volunteers continue trying to recover bodies from mudslides and flood zones, government officials began only this week to recognize the magnitude of another problem: Tens of thousands of people have been left isolated in villages and towns by mudslides that have obliterated mountain roadways--roads that were precarious even in the best of conditions.

"The trucks take the food and medicine as far as they can go," said Aldo Ponte Corvo, emergency coordinator for Catholic Charities of the Archdiocese of Mexico. "Then we're using horses, boats or, if necessary, the shoulders of people."

Tens of thousands of villagers have been streaming out of remote locations on foot seeking relief in temporary shelters set up in government buildings, courthouses, schools and gymnasiums in every major town in Puebla's mountainous north. In some of the most heavily damaged villages, initial reports indicated that large numbers of people had been killed, but these proved erroneous when many residents feared lost began turning up in shelters miles away, relief workers said.

Local officials say overall damage may be more extensive than in previous storms because of the tremendous growth of many mountain communities over the past two decades. New settlements, along with roads to reach them, have sprouted on unstable mountainsides that have been weakened in recent years by deforestation and heavy cultivation.

Although thousands of local volunteers and government workers have joined in efforts to clear roadways and deliver supplies, some communities have grown desperate.

On Tuesday in the northern Puebla village of Zacapoaxtla, a group of people armed with machetes attacked a convoy carrying emergency shipments of beans and rice and carried off the provisions, according to the daily newspaper Reforma. Another newspaper, El Universal, quoted the town's mayor as saying that villagers desperate for food had resorted to eating the carcasses of cows, pigs and chickens washed up by the flood waters.

In the nearby highland town of Huauchinango, the mayors of 50 devastated communities--many of whom arrived after long walks from their villages--gathered with government officials Tuesday night to deliver acrimonious pleas for assistance.

"There's no coordination," complained Humberto Olarte Romero, town president of Jalpan, a community 25 miles away. "We're completely cut off. I'm asking for sugar, blankets and oil. [The government is] sending water, water, water. I'm drowning in water."

Another besieged mayor, wearing a plastic-covered cowboy hat, also expressed frustration. "People are asking me if they can stay and rebuild," he said. "I don't know what to tell them. I need engineers. If people come down with illnesses, where will I send them, and how am I going to get them there?"

Government technical adviser Arturo Sanchez Rojas, who stepped out of the meeting for a respite from the mayors' verbal pounding, sighed and said: "We're barely starting, and there are many places yet to get to."

Correspondent John Ward Anderson and researcher Garance Burke in Mexico City contributed to this report.