Rescuers on the Indonesian island of Sulawesi are struggling to reach villages devastated by Sunday's severe flooding and landslides.
At least seven people are known to have died, but officials now say about 50 more are missing and feared dead.
Hundreds of houses were flattened and thousands of people have been forced to leave their homes.
Flooded roads were hampering rescuers and some villages were cut off, Health Ministry official Rustam Pakaya said.
Teams were trying to distribute food and medical aid to the displaced, but were struggling to reach affected areas, he said.
Thousands of people are reported to have been left homeless.
"About 8,000 have been evacuated, but many thousands are still in the area and need to be moved," Reuters news agency quoted Setio Sutarmo, a disaster management official, as saying.
"Yesterday we only had 60 rescuers from the local search and rescue unit and the police. Back up is on the way, but it takes time to reach the area," he said.
Heavy rains regularly cause flash floods and landslides in Indonesia.
Many experts say the problems have been exacerbated by deforestation, which makes it easier for rain to penetrate the soil and dislodge it.