At least 25 people have been killed and dozens are missing as heavy rain caused flash flooding in the US state of Texas.

Officials stated that a further 23 children are missing from a girls' camp after around 10 inches (25cm) of rainfall occurred in just a few hours overnight.

Rescue teams are working to save those trapped in high water, local officials say.

Texas Governor Greg Abbott said search and rescue operations will be "limitless", adding multiple resources will be devoted to the effort.

A person is rescued via helicopter from the flash floods

Speaking to reporters aboard Air Force One, US President Donald Trump said: "We'll take care of them", when discussing federal aid.

Trump described the floods as "terrible", adding that "we're working with [Abbott]" to support those impacted.

The 23 missing children were among more than 700 who were at the summer camp as floodwaters crashed through at 4am local time.

State emergency management officials warned of heavy rain and flash flood threats, but "did not predict the amount of rain that we saw", W. Nim Kidd, director of the Texas Division of Emergency Management, told a news conference.

Some 10 inches (25cm) of rainfall occurred in just a few hours overnight

Elinor Lester, 13, said she and her cabin mates were woken up by a storm at 1.30am and had to be helicoptered to safety.

She said: "The camp was completely destroyed," describing the situation as "really scary".

Kerr County Judge Rob Kelly, the top local elected official, said: "Everybody is doing everything in their power to get these kids out.

"We have floods all the time. This is the most dangerous river valley in the United States."

When reporters pressed Kelly about why more precautions were not taken, he emphasised that "we had no reason to believe this was going to be anything like what's happened here. None whatsoever."

People watch as the flash flood sweeps through

Lieutenant Governor Dan Patrick said the Guadalupe River had risen 26 feet (eight metres) in 45 minutes as heavy showers soaked the region.

Patrick said: "We're praying for all of those missing to be found alive. We're doing everything we can to get in there."

As of Friday night, 237 people have been rescued or evacuated, with an additional 167 by helicopter, according to Major General Thomas Suelzer, the adjutant general for the state of Texas.

Further rain is forecast in the region, with flash flood warnings extending for at least 180miles of Texas for the next couple of days.