North Korea preparing nuclear test, South Korea says

North Korea may be preparing for a fourth nuclear test, South Korean officials say.

South Korean Unification Minister Ryoo Kihl-jae told lawmakers there are "signs" of increased activity in the North's main nuclear test site.

A newspaper also quoted a South Korean official confirming activity similar to the North's third test on 12 February.
This comes amid North Korea's stepped up rhetoric in recent weeks against the US and South Korea.
Mr Ryoo did not elaborate on the specific intelligence.

But when asked about a news report that North Korea had stepped up activity at its underground atomic test site, he said "there are such signs".

Newspaper JoongAng Ilbo quoted an unnamed South Korean official as saying that South Korean intelligence has detected "increased activity of labour forces and vehicles" at the Punggye-ri nuclear test site in the country's north-east.

"We are closely monitoring the ongoing situation, which is very similar to the situation ahead of the third nuclear test," the official told the newspaper.