Two minor natural earthquakes hit near North Korea's nuclear testing site Monday, South Korea's state weather agency said.

A 2.3 magnitude tremor occurred about 36 kilometers north-northwest of Kilju, North Hamgyong Province, at 2:33 p.m., according to the Korea Meteorological Administration (KMA).

At 7:47 p.m., another 2.3 magnitude quake struck about 37 kilometers north of the region, where North Korea's Punggye-ri nuclear testing site is located, the KMA said.

Both are presumed to have occurred naturally, the agency added.

They followed a 3.1 magnitude natural earthquake that struck the region Friday.

The epicenter of Monday's first quake was at a latitude of 41.27 degrees north and a longitude of 129.24 degrees east at a depth of 22 km, according to the KMA.

The epicenter of the second tremor was at a latitude of 41.28 degrees north and a longitude of 129.26 degrees east. It was 18 km deep.

Over 20 earthquakes with a magnitude of 2.0 or bigger have struck regions near Kilju since 1978, with a 3.2 magnitude quake that occurred Sept. 23, 2017, being the strongest.

So far, eight quakes with a magnitude of 2.0 or bigger have been reported on the Korean Peninsula this year. (Yonhap)