Jakarta, Oct 29 (AFP) A moderate 5.6-magnitude earthquake struck off Indonesia's Sulawesi island today, but there were no immediate reports of damage and no tsunami warning was issued, seismologists said.

The quake struck at 2:21 pm (1051 IST), 168 kilometres at sea southeast of Manado city in North Sulawesi province at a depth of 30 kilometres, the Indonesian Meteorological and Geophysics Agency said.

Indonesia sits on the Pacific "Ring of Fire", where the meeting of continental plates causes high volcanic and seismic activity.

A 7.6-magnitude quake that struck Sumatra island on September 30 killed more than 1,000 people.