HUNT (AFP)

The death toll from catastrophic flooding in Texas rose to more than 100 on Monday, as rescuers continued their search for people swept away by torrents of water.

Among the dead were at least 27 girls and counselors who were staying at a youth summer camp on a river when disaster struck over the Fourth of July holiday weekend.

Forecasters have warned of more flooding as rain falls on saturated ground, complicating recovery efforts involving helicopters, boats, dogs, and some 1,750 personnel.

"There is still a threat of heavy rain with the potential to cause flooding," Texas Governor Greg Abbott said in a statement Monday, with the number of victims expected to rise.

President Donald Trump confirmed he planned to visit Texas on Friday.

Trump has described the floods that struck in the early hours of Friday as a "100-year catastrophe" that "nobody expected."