Police in the southern US state of Arkansas say 12 people have died after flash flooding hit two campsites in the south-west of the state.
Rescuers are still searching for anyone trapped by the flooding, a police spokesman told US media. An unknown number of people are still missing.
The National Weather Service said 7.6in (19.3cm) of rain had fallen overnight.
Two helicopters are also taking part in the search, in a remote, mountainous area visited by hikers and hunters.
Police spokesman Bill Sadler told US network CNN: "We believe there are still individuals trapped in the area.
"The primary mission of the Arkansas state police working with the local authorities right now is to get the living out of that area and locate the dead."
Officials were bringing in a refrigerated truck to act as a temporary morgue, he said.
It is not clear whether all those killed were staying at the campsites washed away by the flash floods.
The flood damage is centred around the Camp Albert Pike area, 75 miles (120km) west of the state capital, Little Rock, the Associated Press (AP) news agency reports.
The helicopter search operation is focused on campsites along the Little Missouri and Caddo rivers.
National Guard troops are helping to look for those affected.
Arkansas Governor Mike Beebe told AP the deaths had occurred at about 0530 local time, when the floodwaters reached their peak.
Rescuers are still searching for anyone trapped by the flooding, a police spokesman told US media. An unknown number of people are still missing.
The National Weather Service said 7.6in (19.3cm) of rain had fallen overnight.
Two helicopters are also taking part in the search, in a remote, mountainous area visited by hikers and hunters.
Police spokesman Bill Sadler told US network CNN: "We believe there are still individuals trapped in the area.
"The primary mission of the Arkansas state police working with the local authorities right now is to get the living out of that area and locate the dead."
Officials were bringing in a refrigerated truck to act as a temporary morgue, he said.
It is not clear whether all those killed were staying at the campsites washed away by the flash floods.
The flood damage is centred around the Camp Albert Pike area, 75 miles (120km) west of the state capital, Little Rock, the Associated Press (AP) news agency reports.
The helicopter search operation is focused on campsites along the Little Missouri and Caddo rivers.
National Guard troops are helping to look for those affected.
Arkansas Governor Mike Beebe told AP the deaths had occurred at about 0530 local time, when the floodwaters reached their peak.