PORT-AU-PRINCE, Haiti—Rescue teams in Haiti scrambled Friday to get urgent aid to victims of Hurricane Matthew after the death toll rose into the hundreds, amid fears the numbers could rise sharply as the extent of the devastation becomes clearer.

A Haitian government official, speaking on condition of anonymity, said Friday that the documented death toll is 271, citing sources such as hospitals, mayors, departmental delegates of the presidency and civil protection authorities. There have been unconfirmed reports of many more fatalities.

There was confusion over the death toll, with various media citing different local officials saying the fatalities had climbed past 500.

“The number of fatalities is still coming in, still growing,” said Marc Vincent, the Haiti representative for the United Nations Children’s Fund. “The more we’re able to get out to different areas, the more we’re able to see that is a major humanitarian catastrophe.”

The hardest-hit area was the country’s southwest peninsula and the towns of Jérémie and Les Cayes, which were directly in the path of the Category 4 storm when it hit, the most powerful Atlantic storm in years.

“Jérémie is a nightmare, a real catastrophe,” said Msgr. Pierre-Andre Pierre, the president of Haiti’s Catholic University, who toured the area by helicopter Thursday. “The priests are praying, but it’s not enough. The people need food, they need water, they need shelter.”

All the houses in Jérémie, a seaside city of about 30,000, have had their roofs torn off, he said. “Everybody is on the street with their belongings, all wet and muddy. It’s a real tragedy,” he said.

It is the same situation in the Les Cayes, another seaside city of about 70,000 people. “Cows, chickens, pigs, they are all gone,” he said.

Complicating relief efforts, a bridge collapsed on the main road that connects the capital of Port-au-Prince to the peninsula. “The biggest challenge right now is logistics,” said Stephan Coles, chief executive of Coles Group, a Haitian food company that was helping organize relief supplies.

Mr. Vincent, of the U.N. Children’s Fund, said nearly all the 1.3 million residents of the Grand’Anse and Sud departments at the western end of the peninsula had been affected in some way by the storm.

He said there are reports of 30,000 families being displaced in Grand’Anse, 60,000 homes damaged and 20,000 severely damaged, and two thirds of schools out of action. In neighboring Sud some 25,000 people are in provisional shelters or without shelter, he added.

Relief organization World Vision estimated that on the island of La Gonâve, 40% to 50% of homes were damaged or destroyed, and thousands of people injured. Roads on the island are washed-out or muddy, and the group used boats to distribute supplies.

“We fear that despite the jump in the death-toll figures, they may continue to rise in the coming hours and days, especially as people gain access to the hardest hit areas,” said John Hasse, World Vision’s country director for Haiti.

He said aid distributions are likely to pick up Friday as the weather clears and some local roads are opened.

“There are areas where people haven’t eaten much or had access to clean water in days. Each time we reach a new remote area, people rush up to our teams desperate for supplies,” he said.

The U.S. Southern Command sent the Navy dock ship USS Mesa Verde to Haiti, with four helicopters, one landing craft and 300 Marines to help distribute emergency aid. They will join some nine other helicopters and 250 personnel already in the area, Southern Command said in a statement.

At a warehouse near the U.S. Embassy in the Tabarre section of Port-au-Prince, dozens of volunteers from local schools gathered Friday to start packing 30,000 kits filled with milk, canned fish, pasta, cooking oil, water disinfectant and personal hygiene supplies to send by barge to the Southwest.

Three days after the storm, many Haitians are leaving shelters and returning to their homes, some to try to make repairs or salvage what they can.

LES CAYES, Haiti — A hospital now a shambles, its floors swamped with garbage and water, absent electricity. People living in the streets, camped in front of their broken homes. Buildings smashed into splinters. Farm fields flattened, portending a hard year ahead.

“For me, Roche-à-Bateau is not a place to live anymore,” said Warens Jeanty, 26, a tourism operator surveying the beach towns and picturesque port hamlets that dot Haiti’s coast. “People have nowhere to stay.”

As Haiti picks through the detritus left by Hurricane Matthew, more bodies are turning up every hour. Some estimates said that more than 800 people had died in the storm, more than double what the government has reported, though it acknowledged that the toll was unknown. In one part of the country’s southern peninsula, nearly 30,000 homes were destroyed and 150 lives lost, officials said.

And a full accounting of damage has not even started.

“I had never seen anything like this,” said Marie Yolene Gateau, a retired New York City guidance counselor who lives in Leogane, Haiti, a town that was largely flattened in the 2010 earthquake. Now the storm has wiped out most of the region’s sugar crop, bananas and mangoes, she said. “The hurricane was attacking the trees. I watched thinking, ‘When is it going to stop?’ ”

Passage to many areas remained blocked, thwarting efforts to assess the destruction and to help survivors. A single remote village reported 82 dead on Friday, while others said they were waiting to account for dozens of missing people. The government, which requires visual proof to count a death in its toll, could hardly keep up with the accounts of loss stitched together from hospitals.

“We’re still far from having a full picture of the extent of the damage,” said Marc Vincent, a Unicef representative in Haiti. “We are hoping for the best, but bracing for the worst.”

It is a state that Haiti has grown accustomed to.

The country was getting ready for elections this Sunday, the product of nearly a year of wrangling and recriminations. But after a long period of political uncertainty and delay, even nature would not let Haiti hold the vote.

Now the hurricane has presented yet another hurdle to a nation still grappling with the devastation of the 2010 earthquake and a cholera epidemic inadvertently introduced to the country by United Nations peacekeepers.

Etienne Navuson, 27, waited out the hurricane this week in his concrete home as the wind lashed his village on the southwestern peninsula. When he awoke, almost everything had vanished: cattle, crops, fields and homes.

“Had the rain fallen more than it did — had it gone for just one more hour — we would have lost even more,” Mr. Navuson said.

At least 90 percent of the village was destroyed, he said. Residents are searching for food and water buried in the rubble.

“Those who find something are fortunate,” he said. Seven more family members have taken refuge in Mr. Navuson’s home after losing their own to the storm. The tiny home is now packed with people sleeping on plastic sheets for bedding.

“There will be food shortages in the days to come,” Mr. Navuson said.

Msgr. Pierre-André Pierre, the head of the Catholic University of Notre Dame of Haiti, encountered chaos when he reached the coastal town of Jérémie. Trees were gone, leaving an empty field. Someone had discarded a body in front of a Catholic bishop’s house, not knowing where else to dispose of it.

The monsignor said he then took a flight to the southern part of the peninsula where he passed over the town of Roche-à-Bateau, where little was left.

“That town did not exist,” he said.

Jeff Barnes, a Haitian-American pilot, was making relief flights on Friday. Many of the towns around Jérémie remained cut off from the rest of Haiti. In some neighborhoods, 80 to 90 percent of homes had been severely damaged or destroyed.

Swaths of trees had been reduced to stumps, he said. Large teams of young people had taken to the streets with machetes and chain saws, trying to clear roads blocked by fallen trees, some several feet in diameter.“ Almost everyone is living under the sky now, sleeping under the stars,” he said. “Doors are gone, people don’t have a place to live.”

Observers said that the hurricane and the lack of a coordinated response recalled the troubles the country faced during the 2010 earthquake.

“It is during natural disasters such as this the frailty and near-absence of Haiti’s state becomes most visible,” said Michael Deibert, the author of two books on Haiti. “As the country slides downhill, the political elites squabble in the capital and the international community fails to come up with an effective way of engaging with Haiti’s most vulnerable.”

Others agreed.

“Haiti has been in the path of the storm just way too often,” said Robert E. Maguire, a professor of international affairs at George Washington University. “It isn’t because of anything the Haitian people are doing. It’s natural disasters exacerbated because of the way people have managed the country.”

The nation’s politics, meanwhile, often brew their own type of disaster, leaving the country bereft of clearly elected leaders.

The interim government is still assessing the damage. Haiti’s Civil Protection Force maintained on Friday that fewer than 300 people had died, but Reuters had tallied that nearly 900 lives were lost.