European monitoring agency is reporting North Korea 5.0 magnitude 'quake' may have been a nuclear test

North Korean leader Kim Jong Un looks through binoculars at the site of a ballistic missile launching earlier this month.

A European monitoring agency is reporting a 5.0 magnitude quake near North Korea's northeastern nuclear test site. There was no immediate confirmation of a nuclear test, which such seismic activity has previously indicated.

South Korea's Defense Ministry said today it could not immediately confirm the cause, and the country's weather agency said it was analysing what might have happened. But the US Geological Service reported an "explosion" in the area.

North Korea conducted its fourth nuclear test this year, part leader Kim Jung Un's push for a nuclear-armed missile that could reach the US mainland.