SEOUL -- South Korean President Moon Jae-in said Thursday that Japan should accept his government's need to respect recent court rulings involving wartime labor victims, as relations between Tokyo and Seoul continue crumbling under the weight of a growing pile of disputes.
The failure to resolve these issues through communication has prompted Japanese lawmakers to consider the risks of taking punitive measures against South Korea.
Moon told reporters at his New Year's news conference Thursday that South Korea's separation of powers among the executive, legislative and judicial branches means "there is nothing [the government] can do" about the rulings.
The president made his first public comments on the issue since the country's Supreme Court in October ordered Japan's Nippon Steel & Sumitomo Metal to compensate South Koreans forced into labor during World War II. A South Korean court has since granted a request to confiscate company assets in the country.
Moon cited the countries' "unfortunate" history as the root of the deteriorating relations, and he said that Japan should take a "more modest position."
"The politicization of this issue by Japanese politicians and political leaders, however, is not a wise stance to take," Moon said.
South Korean media have accused Japanese Prime Minister Shinzo Abe of using disputes with Seoul to shore up conservative support as he prepares for upcoming elections. Japan's statements have stirred nationalist sentiment in South Korea, while Moon has blamed the worsening relations on Tokyo.
Recent problems between the neighboring countries go beyond wartime labor. South Korea decided in November to dissolve a foundation for wartime "comfort women" set up with Japanese money, and a South Korean warship locked fire-control radar onto a Japanese patrol plane in December.
Talks on these issues have not progressed, and mutual distrust has grown. One hurdle involves the exclusion of Japan experts from South Korea's diplomatic decision-making.
South Korean prosecutors are investigating ousted President Park Geun-hye over delayed rulings on wartime labor cases. Diplomats who brokered the 2015 comfort women deal with Japan under her administration have come under fire as part of these efforts.
"Communication between the Moon administration and Japanese government has stagnated," said a veteran of South Korea's Ministry of Foreign Affairs. Meanwhile, Moon has focused primarily on the economy and North Korea amid slumping support at home.
Tokyo and Seoul also have dug in their heels over the radar incident in the Sea of Japan.
South Korea's defense ministry released a video in eight languages challenging Japan's stance on what happened, while the military is drafting a manual on how to respond to aircraft from friendly nations flying on a threatening path, as Seoul claims the Japanese plane was doing at the time of the incident.
Japan requested intergovernmental talks Wednesday over the court rulings in line with a 1965 treaty normalizing relations between the two countries, but Moon has not responded. South Korean Prime Minister Lee Nak-yon, to whom the president has delegated the issue, has told Japan that a resolution will take time.
A plaintiff group of former wartime laborers will propose an out-of-court settlement Jan. 18 to Mitsubishi Heavy Industries, another Japanese company ordered to pay damages. If Mitsubishi Heavy does not respond by March 1, the group will begin procedures to seize the company's South Korean assets. Another civic group will hold an information session Jan. 25 for those interested in additional lawsuits against Nippon Steel.
Japan's ruling Liberal Democratic Party has only toughened its stance against South Korea in response to these developments.
"I can't believe [Moon] would make such statements based on the situation," Fumio Kishida, who chairs the party's policy research council, told reporters Thursday. "It is highly disappointing."
Kishida said he often hears "frustration and outrage from regional districts" across Japan.
The LDP will debate responses to these disputes Friday in Tokyo. Proposals include temporarily recalling Japan's ambassador to South Korea, suspending visa exemptions for South Koreans, imposing tariffs on South Korean products and seizing the Japanese assets of South Korean companies.
But these measures carry risks and difficulties. Scrapping visa exemptions would run counter to the government's goal of drawing 40 million annual visitors to Japan by 2020. Recalling the ambassador would leave Tokyo without a leader on the front lines in its talks with Seoul. Tariff hikes and asset seizures would require new legal frameworks.
The trigger for these countermeasures remains uncertain as well. Should intergovernmental talks prove unsuccessful, Japan intends to begin arbitration procedures based on the 1965 treaty. Tokyo is considering filing a suit to the International Court of Justice should that fail as well, but Seoul may not respond.
Japan also could take economic measures, but South Korea might file an appeal to the World Trade Organization, where a loss would deliver a devastating blow.
The deteriorating relations risk harming collaboration with the U.S. on North Korea. The three countries have conducted joint missile defense exercises and cooperated to prevent North Korean smuggling on the seas.
The U.S. often has acted as mediator when relations between Tokyo and Seoul soured in the past. But President Donald Trump has ambitions to resolve issues with North Korea by himself, leaving no one to play peacemaker for the quarreling neighbors.
Nikkei staff writer Tomohiro Ebuchi in Tokyo contributed to this story.