At least 43 people have died and dozens of children are missing in the Texas Hill Country after catastrophic flooding, with officials warning the casualty count will climb as forecasts call for more rain and the risk of further flash floods in the coming days.

Rescuers searched through the night early Sunday for 27 girls missing from a riverside summer camp in Texas, after torrential rains caused devastating floods that killed at least 50 people in the US state.

Extreme flooding has left at least 32 dead in Kerr County. Some two dozen kids are missing from Camp Mystic, a Christian girls camp.