At least 48 people have reportedly been killed after a strong 7.5 magnitude earthquake and tsunami struck Indonesia.
Waves of up to 2m (6.6ft) high swept through the city of Palu on Sulawesi island after the quake brought down several buildings and sent people fleeing from their homes.
Disaster agency spokesman Sutopo Purwo Nugroho said four hospitals in Palu have reported 48 dead and hundreds of injured, adding that many victims were still unaccounted for.
A magnitude 6.1 earthquake which earlier hit central Sulawesi also reportedly killed one person and injured 10 others, as well as damaging dozens of houses.
Authorities are struggling to coordinate the rescue effort because a power outage has cut communications around Palu and the nearby town of Donggala, which is closest to the epicentre of the quake.
Officials said initial reports showed some victims in the rubble of collapsing buildings.
Mr Nugroho said: Bodies of victims were found in several places, because they were hit by the rubble of collapsing buildings or swept by tsunami… but we are still collecting data.
The 7.5 earthquake hit at a depth of 10km (6.2 miles) just before 6pm local time (12pm UK time) on Friday, the US Geological Survey said.
A tsunami warning was issued but lifted within the hour.
Footage posted online showed waves of water bring down several buildings and inundate a large mosque in Palu.
More than 600,000 people live in Donggala and Palu.
The 7.5 magnitude tremor on was more powerful than a series of quakes that killed hundreds on the Indonesian island of Lombok in July and August.
Indonesia is prone to earthquakes because of its location on the Ring Of Fire, an arc of volcanoes and fault lines in the Pacific Basin.
In December 2004, a massive 9.1 magnitude earthquake off Sumatra in western Indonesia triggered a tsunami that killed 230,000 people in a dozen countries.