An earthquake measuring magnitude 5.5 has hit off the South Korea's southeastern coast, news agency AP reported Wednesday citing local media sources.
Yonhap news agency says the quake was detected about 6 kilometres (4 miles) north of the southeastern port city of Pohang.
Residents in the capital Seoul, more than 300 kilometres (186 miles) away, say they've felt tremors and are reporting their buildings have been shaken.
South Korea has relatively little seismic activity, unlike neighbouring Japan.