South Korea said Tuesday it is "very concerned" over Japanese leaders' negative reaction to last week's top court ruling in which a Japanese company was ordered to pay compensation for wartime forced labor.

The Foreign Ministry, in a statement, accused Japan's leadership of being "not concerned about the root of the problem" and of "continuing to speak out (in ways that) stimulate our national feelings."

Separately, Im Jong Seok, South Korean President Moon Jae In's chief of staff, voiced displeasure earlier in the day about Japan's reaction, saying it is "very inappropriate and regrettable."

On Oct. 30, South Korea's Supreme Court upheld a lower court ruling that ordered Nippon Steel & Sumitomo Metal Corp. to compensate four South Koreans for forced labor during Japan's colonial rule of the Korean Peninsula from 1910 to 1945.

Last Thursday, Japanese Prime Minister Abe called the ruling "unbelievable" and indicated Tokyo could take the case to the International Court of Justice, while the ruling Liberal Democratic Party adopted a resolution urging the government to study that and other options.

On Sunday, Japanese Foreign Minister Taro Kono strongly denounced the South Korean court's decision, calling it a "challenge against international law."

A South Korean Foreign Ministry official said the government must respect the court's judgment in accordance with the principle of the separation of administrative, judicial and legislative powers, in an indication that the government will not intervene in the verdict.

The official went on to say that Tokyo should recognize that excessively politicizing the issue is not helpful in building future-oriented bilateral relations, and that Seoul is studying how to achieve justice while maintaining a strategic bilateral relationship.

Japan maintains that the issue of compensation related to the period was settled under an agreement attached to a 1965 treaty that established diplomatic ties between Japan and South Korea.

Fourteen similar suits have been filed against Japanese companies, including Mitsubishi Heavy Industries Ltd., Nachi-Fujikoshi Corp. and Hitachi Zosen Corp.