A Tsunami warning has been issued in Indonesia prompting some concerned residents to flee for higher ground, according to reports.
An earthquake, which struck out at sea at a revised depth of 36 km and was followed by several smaller aftershocks, prompted the alert.
There were no immediate reports of casualties following the tremors, which struck off the north-eastern coast of the island of Sulawesi.
A graphic posted on Twitter by Indonesia's geophysics agency predicted waves of half a meter (1.6 feet) for parts of North Sulawesi and North Maluku.
There were conflicting reports of the quake's magnitude, with some placing it at 6.9 and others 7.1.
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 130 km from the epicenter, sustained minor damage and had to evacuate patients, according to reports.
Radio El Shinta reported that residents in Manado, North Sulawesi's provincial capital, ran from their houses.
Indonesia, a vast archipelago of 260 million people, is frequently struck by earthquakes.
It is also blighted by volcanic eruptions and tsunamis because of its location on the Ring Of Fire, an arc of volcanoes and fault lines in the Pacific Basin.
There were no immediate reports of major damage or casualties.
Additional reporting by agencies.
