The epicentre of the quake was located 128 km southeast of East Bolaang Mongondow Regency, the agency said.
Its depth was 10 km under the seabed, Xinhua news agency reported.
The quake struck at 01:56 a.m. Jakarta time Thursday (1856 GMT Wednesday), according to the agency.
The agency did not issue a tsunami warning as the tremors would not trigger giant waves.
Indonesia, an archipelagic country, is prone to earthquakes due to its position in the vulnerable zone called the Pacific Ring of Fire.
Details are awaited.
