The Korea Meteorological Administration(KMA) said a magnitude five-point-four earthquake hit nine kilometers north of Pohang's northern district in North Gyeongsang Province at around 2:29 p.m. on Wednesday. 

At 2:49 p.m., a magnitude three-point-six earthquake hit seven kilometers north of Pohang's northern district. 

The KMA said another quake measuring magnitude four-point-six was detected at 4:49 p.m., eight kilometers north of Pohang's northern district. 

The National Fire Agency said ten people were lightly injured as of 5 p.m.

Tremors were felt around the country, including in Seoul and Busan. 

The weather agency said the seismic center for the initial quake is 36-point-one degrees north latitude and 129-point-37 degrees east longitude. 

It said the information was estimated automatically using seismic waves. It cautioned against aftershocks. 

Korea Hydro and Nuclear Power said nuclear power plants in the country are operating normally. 

The initial quake was the second-strongest ever to hit South Korea after last year'a magnitude five-point-eight earthquake in the nearby city of Gyeongju.