A huge earthquake has rocked South Korea prompting fears Kim Jong-un may have completed another nuclear test.

The 5.4-magnitude quake in the south east of South Korea was felt in the capital Seoul and caused buildings to shake.

It comes after another nuclear test by North Korea in September caused a 3.4-magnitude earthquake and took place near one of the rogue state's test sites.

An earthquake measuring magnitude 5.5 has hit off the coast of South Korea

Debris from a collapsed building is scattered in front of a shopping center after an earthquake

The earthquake shook South Koreaís southeastern coastal region on Wednesday afternoon, but no casualties were immediately reported

No casualties have been reported following today's tremor and no tsunami warning has been issued.

The earthquake's epicentre was 9.3km (5.8 miles) northwest of the port city of Pohang, according to the U.S. Geological Survey.

South Korea's state-run Korea Meteorological Administration measured the quake at the same strength but said the epicenter was inside Pohang.

Residents in the capital, more than 300 kilometers (186 miles) away, felt tremors and said their buildings shook.

A number of windows were broken and walls crumbled beneath structures close to the central point of the earthquake.



The Korea Meteorological Administration reported a second tremor, with a magnitude of 5.4, about nine kilometers from Pohang.

The agency sent out an earthquake alert via a mobile network which asked some of the local residents in the affected area to evacuate immediately.

South Korean media showed crumbled walls piled on parked cars, broken windows from some buildings and elementary school students taking shelter on a playground.

No injuries or major damage has been reported, according to the Korea Meteorological Administration.

Residents in the capital, more than 300 kilometers (186 miles) away, felt tremors and said their buildings shook

Some buildings across the nation were impacted by the earthquake (pictured)

The violent tremor was detected near Pohang in the North Gyeongsang Province

It's the strongest quake in South Korea since a 5.8-magnitude occurred near the ancient city of Gyeongju, which is close to Pohang, in September 2016, Korea Meteorological Administration officials said.

South Korea has relatively little seismic activity, unlike neighboring Japan.

The nuclear power plant Singori 3 in Ulsan is believed to remain unaffected by the quake.

Around 2:50pm (local time) a third aftershock with a magnitude of 3.6 was detected about 7 kilometers north of Pohang.