(Bloomberg) -- Indonesia’s meteorological agency warned of more aftershocks after a 6.9 magnitude earthquake hit southwest Sumatra early on Wednesday and said the tremor posed no risk of a tsunami.

The epicenter of the quake was at sea, 169 kilometers Southwest of Bengkulu, the Meteorology, Climatology, and Geophysics Agency said on Twitter. The impact of an aftershock measuring 6.8 on the Richter scale was more pronounced as its epicenter was closer to the shore, it said.

While there were no reports of casualties or major damages to buildings yet, the meteorological agency warned people to avoid buildings with cracks, which may collapse easily.

Indonesia’s 17,000 islands are prone to earthquakes because the country straddles the Pacific Ring of Fire, an arc of fault lines and volcanoes that causes frequent seismic upheavals. More than 4,000 people were killed in Central Sulawesi after an earthquake and tsunami struck the island in 2018.

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