A 6.9 magnitude earthquake has struck off the northeast coast of Indonesia's Sulawesi island.
The quake struck out at sea at a revised depth of 36km and several smaller aftershocks followed, according to the Indonesian geophysics agency BMKG.
There were no immediate reports of casualties.
Authorities issued a tsunami warning for eight cities.
The agency had not lifted the warning over an hour after the quake, a spokesperson told Reuters.
"We have not ended it because we are still monitoring the tide gauges for high waves ... though none have been recorded yet," official Rahmat Triyono of the agency BMKG told Kompas TV.
Residents in some cities panicked as tremors shook buildings and authorities urged people to seek higher ground.
Some hospitals in the city of Ternate, around 130km from the epicentre, sustained minor damage and had to evacuate patients, according to media.
Residents in the seaside resort city of Manado, 185km from the epicentre, said the quake was felt strongly for several seconds but no damage was reported.