At least 78 people have been confirmed dead in central Texas, and another 41 are missing following flash floods on Friday.

Sixty-eight of the fatalities, including 28 children, occurred in Kerr County, where a riverside Christian girls' camp was deluged. Ten girls and a counsellor from Camp Mystic are still missing.

Officials say the death toll is certain to rise. More storms are expected in the next 24-48 hours in the region, which could hamper rescue teams who are already facing venomous snakes as they sift through mud and debris.

Three days after the inundation, one of the largest search-and-rescue efforts in recent Texas history was shifting towards a recovery operation.

Of those recovered in Kerr County, 18 adults and 10 children have yet to be formally identified.

Texas Governor Greg Abbott said on Sunday that authorities would "stop at nothing" to ensure every missing person is found.

"It was nothing short of horrific to see what those young children went through," said Abbott, a day after he toured the area.

A major focus of the search has been Camp Mystic, a popular summer camp for girls perched on the banks of the Guadalupe River, which suffered significant damage.

The catastrophe unfolded before daybreak on Friday as the river rose 26ft (8m) in the span of just 45 minutes while most campers were asleep.

Several young campers and the camp's longtime director, Richard "Dick" Eastland, are among the dead.

Greg Froelick, a former Navy Seal and volunteer with the rescue group 300 Justice, is helping the effort to find survivors.

Speaking to the BBC, he said he had heard of victims being found up to eight miles downriver from where Camp Mystic once stood.

He said he has seen "clothing and items from the camp dressers scattered everywhere, up and down the river".

There is also uncertainty about how many other people were camping in the area for the Fourth of July weekend, and how many may have been swept away in the floods.

A two-lane highway that skirts the Guadalupe River and connects the city of Kerrville to Camp Mystic is a scene of devastation.

Ravaged homes are surrounded by fallen trees and furniture on lawns. Fences are toppled and utility lines are down in some areas.

President Donald Trump signed a major disaster declaration on Sunday for Kerr County, activating the Federal Emergency Management Agency to Texas. He also said he would probably visit the state on Friday.

"We're working very closely with representatives from Texas, and it's a horrible thing that took place, absolutely horrible," Trump said on Sunday in New Jersey.

On the ground, local residents are stepping up to support relief efforts - collecting supplies, offering shelter, and doing what they can to help neighbours displaced by the storm.

Alma Garcia drove in from the city of San Antonio to deliver home-cooked meals to residents and volunteers helping with the clean-up effort.

The BBC saw her pull over on the side of the road and take off a top layer T-shirt to give to a resident.

"She was all wet, I told her she's going to need it," Ms Garcia told the BBC.

Local resident Perla started collecting clothes and shoes on Friday after she finished her shift at Walmart. She dropped them off at a shelter the next morning.

"I've never seen something like this before," she told the BBC.

Meanwhile, well wishes poured in from around the world.

In Rome, Pope Leo XIV offered special prayers on Sunday for the bereaved in Texas.

"I would like to express sincere condolences to all the families who have lost loved ones, in particular their daughters who were in summer camp, in the disaster caused by the flooding of the Guadalupe River in Texas in the United States," the pontiff said.

"We pray for them."

Angélica Casas and Alex Lederman contributed to this report