TAIPEI (Taiwan News) – South Korea has reported 156 incidents of illegally exporting strategic materials, some of which could be used to produce chemical weapons, in a report from the country’s own trade ministry.

This indicates that hydrogen fluoride and other items have been shipped illegally over the past four years to countries that include Vietnam and the United Arab Emirates, according to Japan’s public broadcasting organization NHK.

The report cites a South Korean expert as saying exports included substances that can be used to make chemical weapons, such as sarin gas and VX nerve agent. VX is believed to have killed Kim Jong-nam, eldest son of the late North Korean leader Kim Jong-il, in an apparent assassination in Malaysia, in 2017.

Japan has ramped up efforts to curb exports to South Korea for materials vital to the manufacture of high-tech products, particularly in the highly competitive semiconductor sector industry. The Abe government claims multiple cases of illicit exports that potentially serve a military purpose, due to inadequate controls by South Korea, said NHK.

In response, the South Korean government argued most of the cases were carried out by small companies that did not know the goods were categorized as strategic or subject to export controls. Measures have been adopted to crack down on such practices, the government added.

The move by Japan to tighten exports has sparked protests and calls for boycotts of Japanese products in South Korea. The decision has been slammed for being a retaliatory action against a South Korean court ruling that Japanese companies should compensate forced World War II laborers.