Former Prime Minister Fumio Kishida expressed concern about political upheaval in South Korea undermining progress in bilateral relations.

“Political stability in South Korea is crucial for advancing Japan-South Korea relations,” Kishida said in an interview on Thursday after a stunning move by South Korean President Yoon Suk Yeol to impose and later revoke martial law.

Kishida, who left office in September, formed a warm relationship with Yoon over frequent meetings, sometimes in casual settings over drinks. Ties between the nations became as close as they have been in recent decades, leading to a range of cooperation, including the creation of a system to share directly real-time information about North Korean missile launches.