The quake hit the Chishang township in rural southeastern Taiwan and had a depth of 10 kilometers.
Japan’s Meteorological Agency issued a tsunami warning for Miyako island in the East China Sea, but the agency later removed the warning.
Photos showed collapsed buildings in southern Taiwan following the powerful earthquake. The USGS initially registered it at 7.2, before downgrading it to 6.9.
Three people are trapped under the rubble of one building, the island’s official Central News Agency (CNA) reported. A fourth person was rescued.
About 20 passengers were evacuated after a train derailed in the area, but there were no casualties from the incident, the Taiwan Railway Administration said.
Kolas Yotaka, a former presidential spokeswoman who is running for local elections in Hualien county, said that damages were also reported at a local school.
Taiwan’s President Tsai Ing-wen activated the island’s Central Emergency Operation Center following the quake. Taiwanese residents have been asked to stay alert to avoid potential aftershocks, Tsai said in a recorded statement.
About 110 soldiers have also been deployed in Hualien county, along the island’s eastern coast, to assist with disaster relief efforts, Taiwan’s defense ministry spokesman Sun Li-fang said.