TOKYO - Japanese Prime Minister Shigeru Ishiba said Wednesday that Japan was carefully watching the situation in South Korea with "particular and grave" concerns, according to Kyodo News.

"We have been monitoring (developments) since the overnight declaration of martial law with particular and grave concerns," Ishiba told reporters, adding that he is not in a position to comment on South Korea's domestic affairs.

"We don't know the exact details of what happened, but declaring martial law is a serious matter," Kyodo News cited a source from Japan's Ministry of Foreign Affairs as saying.

The situation in South Korea might be chaotic, and Japan will monitor how the situation unfolds, the source added.

South Korean President Yoon Suk-yeol declared an emergency martial law Tuesday night and lifted it early Wednesday following the National Assembly's vote against it.

In accordance with the constitution, the president should lift martial law when the 300-member parliament demands the lifting with a majority of lawmakers voting in favor.