North Korean leader Kim Jong-un has called in his ambassadors and heads of other overseas missions to Pyongyang, sources said Thursday.

The heads of the North's embassies and other missions were brought in for what is presumed to be an ambassadorial meeting, according to the sources.

It has not been confirmed yet whether the meeting is an annual event or a specially arranged one, the sources said.

The North reported on its 43rd ambassadorial meeting in July 2015, but no such reports have been compiled ever since.

The meeting, if confirmed, would come about a month after leader Kim Jong-un met with US President Donald Trump in Singapore and agreed to work toward the "complete denuclearization" of the Korean Peninsula.

Observers say that the meeting might be intended for Kim to instruct policy directions and encourage hard work ahead of the 70th anniversary of the establishment of the North Korean regime on Sept. 9.

Seoul's unification ministry said that it has yet to confirm relevant information on the matter, adding that it is closely monitoring developments in the North. (Yonhap)