At least 48 people were killed by a quake-tsunami in an Indonesian city, the country's disaster agency said on Saturday, announcing its first official death toll.

The agency added that another 356 people were injured in Palu on Sulawesi island where waves as high as 10 feet slammed into the city of about 350,000 people.

The tsunami was triggered by a strong quake that brought down several buildings and sent locals fleeing for higher ground as a churning wall of water crashed into Palu.

Indonesia — A powerful, shallow earthquake hit off the southwestern coast of Sumatra in Indonesia on Wednesday and could trigger a tsunami, officials said. There were no immediate reports of injuries or damage.

The U.S. Geological Service said the earthquake struck Wednesday evening and had a preliminary magnitude of 7.8. It was centred under the ocean at a depth of 10 kilometres, it said.