A 2.5 magnitude earthquake struck North Korea's northeastern region late Sunday.

According to the Korea Meteorological Administration, quake struck at 11:57 p.m. Sunday, centered around 40 kilometers northwest of Kilju, North Hamkyong Province, at a depth of 15 kilometers.

Kilju is where the Punggye-ri nuclear testing site is located.

The South Korean state weather agency said the tremor occurred naturally.

A natural earthquake was detected in the same area on April 19 at a magnitude of 2.7.

Experts believe the effect of past nuclear tests may be attributable to frequent natural quakes Kilju in recent years.

North Korea closed down the testing site in May 2018.