Prime Minister Yoshihide Suga will not visit South Korea without a guarantee that assets seized from a Japanese company following a South Korean court ruling on compensation for wartime labor will not be liquidated, a senior Foreign Ministry official said Wednesday.

The official, who spoke to reporters on condition of anonymity, said that without such an assurance it would be "impossible" for Suga to attend a trilateral summit with China that South Korea seeks to host this year.

Japanese Prime Minister Yoshihide Suga meets the press in Tokyo on Sept. 29, 2020, after speaking by phone with Russian President Vladimir Putin. (Kyodo) 

Relations between Tokyo and Seoul have sunk to historic lows since South Korea's top court in October 2018 ordered Nippon Steel to compensate four plaintiffs for forced labor during Japan's 1910-1945 colonial rule of the Korean Peninsula.

Japan argues the court decision goes against a 1965 agreement between the neighboring countries under which it provided South Korea with financial aid on the understanding that the compensation issue was settled "completely and finally."

Last Thursday, Suga spoke with South Korean President Moon Jae In by phone for the first time since taking office in mid-September and said the leaders "cannot allow our relations to remain as they are."

South Korean President Moon Jae In addresses a ceremony in Seoul on Aug. 15, 2020, marking the 75th anniversary of the end of Japanese colonial rule. (Kyodo) 

Assets held by Nippon Steel in South Korea have been seized and could be liquidated "any day now," the official said, adding that Foreign Minister Toshimitsu Motegi has warned his South Korean counterpart Kang Kyung Wha multiple times that this would do "irreparable" damage to bilateral ties.

Japan, South Korea and China have been holding trilateral summits roughly once a year since 2008, with the host rotating between the three countries. The previous meeting was held in Chengdu, western China, in December last year.