SEOUL: A 2.6 magnitude earthquake struck near a North Korean nuclear test site on Thursday, the latest in a series of natural temblors that hit the region recently, South Korea's state weather agency said.

The tremor occurred about 40 km northwest of Kilju, North Hamgyong Province, at 9:21 p.m., Yonhap news agency reported, citing the Korea Meteorological Administration (KMA).

The epicentre was at a latitude of 41.30 degrees north and a longitude of 129.20 degrees east at a depth of 15 km, the KMA said, adding that the earthquake is believed to be a natural one.

The latest one came on the heels of two separate earthquakes in the day -- one with a 2.5 magnitude that took place at 7:54 a.m. and the other one with a 2.2 magnitude at 12:42 p.m., the weather agency said.

Kilju is home to the Punggye-ri nuclear test site, where North Korea conducted all six of its nuclear tests.