Tsunami warning issued after 7.7 magnitude quake hits off Indonesia coast

Residents along affected coastlines were advised to move to higher ground

A powerful magnitude 7.7 quake has struck off the coast of Indonesia, the U.S. Geological Survey said. No immediate casualties or damage were reported.

The quake hit Indonesia's Flores region with a depth of 10 kilometers at 5:58 a.m. Saturday Indonesia time.

It's epicentre was 68 kilometres north-northwest of the city of Ende in East Nusa Tenggara province.

Indonesia's Meteorology, Climatology and Geophysics Agency issued a tsunami warning and urged residents to stay away from beaches and riverbanks.

The agency located the shallow undersea quake near Flores island.

Residents along affected coastlines were advised to move to higher ground as officials are closely monitoring coastal tide gauges for any changes.

Indonesia, a vast archipelago of more than 17,000 islands, is prone to earthquakes and volcanic activity because of its location on the "Ring of Fire," an arc of volcanoes and fault lines in the Pacific Basin.