The quake was originally reported by the US Geological Survey said as having a magnitude of 6.5. The depth was reported at 12.5 miles.

"The quake was felt strongly for 15 seconds in Palu as people were breaking the fast," said Sutopo Purwo Nugroho, spokesman for Indonesia's National Disaster Mitigation Agency.

"Initial information we received is the access to Kulawi (central Sulawesi) is cut and cars could not get through because there was a landslide. About 40 houses were damaged and a child was injured because the house's wall fell on him," he told Reuters by telephone.

He added that eight houses were "severely damaged" in a nearby area and said that in Indonesia's Aceh province four people died in a flash flood.

Later, a 5.9 magnitude quake struck 150 miles northeast of Ternate, in the Moluccas islands off Indonesia, at a depth of 29 miles, the USGS said.

The Sulawesi quake had no tsunami potential, said Subagiyo, an earthquake centre official in the capital Jakarta.

The US Pacific Tsunami Warning Center said a destructive tsunami was not generated by the earthquake and that the Japan Meteorological Agency may issue additional information on the quake.