JAKARTA - A strong 6.4-magnitude quake struck Indonesia's remote eastern Sumba island Monday, the geophysics agency said.

The quake struck at 7.52pm (1052 GMT, 6.52pm Singapore time) with an epicentre 107 kilometres (67 miles) northwest of the main island town of Waingapu, the Jakarta Meteorology and Geophysics Agency said.

It was measured at a depth of 86 kilometres.

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