JEREMIE, Haiti — Survivors of Hurricane Matthew put on their Sunday finest and picked their way through downed power lines to pray in ruined churches, while desperation grew in other parts of devastated Haiti and international rescue efforts began ramping up.

Haitian authorities were unsure of the extent of the disaster, with some communities still cut off. But tens of thousands of homes were leveled, and the number of dead was in the hundreds.

Guillaume Silvera, an official with the Civil Protection Agency in the Grand-Anse Department, which includes Jeremie, said 522 deaths were confirmed there — not including people in communities cut off by collapsed roads and bridges.

Despite the loss, families packed what remained of the city's churches, many seated in pews under open sky because Matthew ripped away roofs and even walls of the sanctuaries. At least one was so badly damaged that worshippers prayed outside.

Elise Pierre, who said she was about 80, said she believed it was a miracle that she and her loved ones survived.

“If God wasn't protecting us we'd all be gone today, blown into the ocean or up into the mountains,” said Pierre, whose straw hat almost concealed a gash on her forehead she sustained when sheet metal from her roof collapsed during Matthew's fury.

The sound of hammering could be heard on nearly every street in Jeremie, a city near the tip of Haiti's southwest peninsula, as people patched their roofs as best as they could.

On one corner, Jameson Pierre was mixing cement and making blocks. The 22-year-old storm refugee whose family was stuck in an emergency shelter, saw a bright side.

“There will be lots and lots of jobs since so many homes were knocked down. I've been working for the last three days straight,” he said.

He said he was earning about $1 a day.

The first two cargo planes of humanitarian aid from the United States arrived Saturday at the Toussaint Louverture airport in the capital Port-au-Prince. U.S. Ambassador Peter Mulrean said three other planes are expected to arrive in the next few days with more supplies.

Many of the villages in the southwestern peninsula are difficult to reach. And people are growing increasingly desperate after losing everything when the storm ripped through the area Tuesday.

Dony St. Germain, an official with El Shaddai Ministries International, said young men in villages off the road between the southern city of Les Cayes and Jeremie were starting to put up blockades of rocks and broken branches to halt convoys.

“They are seeing these convoys coming through with supplies and they aren't stopping. They are hungry and thirsty and some are getting angry,” said St. Germain.

Government officials estimate that at least 350,000 people need assistance, and concern was growing over an increase in cholera cases following widespread flooding unleashed by Matthew.

An ongoing cholera outbreak has killed roughly 10,000 people and sickened more than 800,000 since 2010, when the infectious disease was introduced into the country's biggest river from a United Nations base where Nepalese peacekeepers were deployed.

The World Food Program said there has been massive destruction of crops.

Hospitals and clinics have been damaged or destroyed as they struggle to deal with an increase in patients with injuries sustained during the storm as well as an apparent increase in cholera.

UNICEF said that in Grand-Anse there were 66,000 houses destroyed and 20,000 heavily damaged.

“Information gathered from various sources in the field suggests that the human toll (dead and injured) will be heavier than the current official figures,” the agency said.