By G9ija

Japan pushed back on Tuesday against calls from South Korea to scrap curbs on some high-tech exports, ratcheting up tension in a decades-old diplomatic dispute that threatens to disrupt the global supply of memory chips and smartphones.

Tokyo said last week it would tighten restrictions on exports of three materials used in smartphone displays and chips, citing a dispute with Seoul over South Koreans forced to work for Japanese firms during World War II.

The moves, which could hit tech giants Samsung Electronics and SK Hynix, among others, spotlight Japan’s sway over a vital part of the global supply chain that the government is now using as a bargaining chip.

Whether Japan implements additional measures depends on South Korea’s response,” Industry Minister Hiroshige Seko told a news conference after a cabinet meeting.

Tokyo was not thinking at all of withdrawing the curbs and they did not violate World Trade Organization rules, he said.

In Seoul, a government official said a South Korean foreign ministry official was expected to discuss the curbs with his counterpart in Washington. Its trade minister was also considering travelling to the United States, a spokeswoman said.

Seko’s comments were an apparent response to South Korean President Moon Jae-in, who urged on Monday that the restrictions be withdrawn. Seoul could not rule out countermeasures for damage inflicted on its firms, Moon added.

South Korea plans to complain to the WTO.

The row shows no signs of abating, with Tokyo threatening last week to drop Seoul from a white list of countries with minimum trade restrictions, hitting the supply of a wider range of items used in weapons production