Seismic security

South Korea is hit by the second most powerful earthquake in its history - prompting fears Kim Jong-un has tested another NUKE

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.

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.