U.S. National Security Adviser John Bolton is likely to visit South Korea later this month to discuss the denuclearization of North Korea. 

Citing diplomatic sources, Japan's Kyodo News agency reported on Thursday that Bolton is arranging a meeting with Chung Eui-yong, the director of the National Security Office in Seoul, around May 28. 

Bolton's possible trip to Seoul is aimed at seeking progress in denuclearization negotiations with North Korea, which have stalled since the second summit between U.S. President Donald Trump and North Korean leader Kim Jong-un collapsed without a deal in February.

Kyodo News reported that Bolton is expected to reaffirm Washington's position that sanctions against the North should be in place until Pyongyang takes concrete steps towards denuclearization.

Citing South Korean government officials, Japan's NHK also reported that Bolton will visit Seoul for talks with Chung near the end of May. 

Earlier, diplomatic sources said Stephen Biegun, U.S. special representative for North Korea, is in the final stages of arranging his own visit to Seoul next Wednesday to Friday to discuss the North Korea nuclear issue.