(Reuters) - A powerful earthquake struck an area southeast of the Indonesian city of Palu on the island of Sulawesi on Monday, prompting people to flee from their homes though there was no tsunami warning issued, officials said.
Sutopo Nugroho, a spokesman for Indonesia's disaster mitigation agency said in a statement the quake lasted around 20 seconds and caused panic and people to rushed out of their houses. Many have stayed outside because of an aftershock.
Earlier, the Indonesian Agency for Meteorology, Climatology and Geophysics said there was no threat of a tsunami following the quake.
Heronimus Guru, operational head of Indonesia's search and rescue agency, said by telephone that he had not received any information about damage or casualties, but was waiting for an update from the disaster mitigation agency.
The USGS had initially put the magnitude of the quake at 6.9, though this was later reduced to 6.6.
The epicentre was 79 km southeast of the town of Palu, the USGS said, in an area northwest of the town of Poso.
(Reporting by Kanupriya Kapoor; Writing by Hugh Lawson and Ed Davies; Editing by Alison Williams)