South Korea on Friday said Japan’s curbs on exports of high-tech materials critical for manufacturing of memory chips was in violation of international law.

The reaction to Japan’s trade restrictions came hours after the Japanese foreign ministry accused Seoul of “overthrowing the legal foundations" established between the two countries in the 1965 treaty to normalize diplomatic ties after World War II.

Kim Hyun-chong, the deputy director of South Korea's national security office, rejected Tokyo's allegations and said Japan had violated international law by taking "unilateral measures" to restrict exports.

“Since this is a measure that seriously damages the World Trade Organization principles, free trade norms and principles advocated by Japan at the recent G20 Summit in Osaka and the global value chain, it is actually Japan who is in breach of international law," Kim said in a statement issued by the South Korean president's office.

Ties between the two soured after Japan on July 4 rolled out the restrictions on exports to South Korea of basic chemical products – fluorinated polyamide, photoresists and hydrogen fluoride – used to manufacture screens and memory chips of computers, servers, TV sets and smartphones.

The restrictions came allegedly in response to the rulings by several South Korean courts – including the Supreme Court – asking Japanese companies to pay compensation to Korean citizens who were forced to work for them during World War II.

Japan, which colonized the Korean peninsula between 1910 and 1945, maintains that all compensation for victims enslaved by Japanese companies was settled during the 1965 Treaty on Basic Relations.

But Kim said in the statement that the South Korean Supreme Court in its 2018 judgment noted that the 1965 agreement "did not cover crimes against humanity and violation of human rights against victims of forced labor”.

"As a democracy, the Republic of Korea (South Korea) can neither ignore nor denounce this ruling," the statement said.

The terse exchange is the latest development in the ongoing bilateral dispute on the issue. South Korea, has announced that it would take the matter to the World Trade Organization.

Japan has not directly linked the export restrictions to the dispute over compensation, but claimed it was a result of deterioration of mutual trust, and to avoid the restricted materials from ending up in the hands of third countries, implying North Korea.

Tokyo had also proposed to set up an arbitration panel to resolve disputes related to the 1965 Treaty on Basic Relations between Japan and the Republic of Korea. But Seoul rejected the proposal citing the Supreme court judgment, although adding that it was open to diplomatic dialog.

In accordance with the 1965 treaty, Japan donated $300 million to the neighboring country. The compensation, however, did not reach the intended victims under the military dictatorship of Park Chung-hee, resulting in thousands of them suing the South Korean government this year. EFE-EPA