However, monitoring agencies have said the likelihood of further casualties was low.

Indonesia's meteorology agency BMKG said there were tsunami waves reported in five locations, with the highest at 0.75 m in North Minahasa in North Sulawesi and about 50 aftershocks were monitored, the largest at a magnitude of 5.8.

Tsunami Warning Lifted

BMKG chief Teuku Faisal Fathani initially said modelling indicated there was tsunami potential for waves of 0.5 m to 3 m high, subsequently the agency lifted the warning by Thursday morning.

Initially, U.S. tsunami warning authorities also said hazardous tsunamis were possible along the coasts of Indonesia, the Philippines and Malaysia, but later lifted the threat warning.

The epicentre of Thursday's quake was roughly 580 km south of the Philippine coast and 1,000 km from Malaysia's Sabah. It struck at a depth of 35 km.

Limited Damage From Aftershocks

Though the epicentre is within 150 km of the densely-populated islands like Ternate and Sulawesi, the USGS said there was 'low likelihood' of further casualties, and they expected limited economic damage.

'Although relatively small, this situation still requires vigilance due to the potential for aftershocks,' Indonesia's natural disaster agency said in a statement. It said initial reports were of minor to moderate damage to several houses and a church, and a fuller assessment was underway.

The statement said tremors from the initial quake were felt strongly for 10 to 20 seconds in Bitung City and Ternate City, and subsequent shocks were located in the sea. The agency urged the public to remain calm and follow guidance until authorities could declare the situation safe.

Alerts Across Pacific Ring Of Fire

Indonesia is a tectonically complex part of the 'Pacific Ring of Fire,' a seismically active belt of volcanoes stretching from South America to the Russian Far East.

The United States Geological Survey said nine other quakes of a magnitude of 7 or more have occurred within 250 km of the one in Indonesia over the last 50 years. These previous quakes had not caused such extensive damage.

The Philippines' seismology agency, Phivolcs, said there was no destructive threat to the country based on the latest data. Meanwhile, Malaysia's meteorological department announced that there was no immediate tsunami threat to the country but that it was monitoring developments.

The Pacific Tsunami Warning Centre warned of the risk of waves less than 0.3 m over tide levels for the coasts of Guam, Japan, Malaysia, Papua New Guinea, the Philippines and Taiwan. Japan may see waves of up to 0.2 m, but no damage is expected, according to the Japan Meteorological Agency.

(With inputs from Reuters)