JAKARTA, Indonesia (AP) — A strong undersea earthquake has hit eastern Indonesia, but there are no immediate reports of serious damage or casualties.

The U.S. Geological Survey says the 6.3-magnitude quake struck Tuesday evening about 110 kilometers (68 miles) off Tobelo, a coastal town on Halmahera Island in North Maluku province. It says the quake was centered about 63 kilometers (39 miles) beneath the sea.

The Indonesian Meteorology and Geophysics Agency said the quake was unlikely to trigger a tsunami.

Indonesia, the world's largest archipelago nation with 240 million people, is prone to seismic upheaval due to its location on the Pacific "Ring of Fire," an arc of volcanoes and fault lines encircling the Pacific Basin.

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