At a press conference on December 27, Russian Foreign Ministry spokeswoman Maria Zakharova warned that Japan's transfer of Patriot air defense missile systems to Ukraine would have serious consequences for Moscow-Tokyo relations, according to Reuters.

The relationship was already troubled before Russia launched its military campaign in Ukraine in February 2022. Japan joined its Western allies in imposing sanctions on Russia and providing assistance to Ukraine, although Tokyo did not supply weapons to Kyiv.

In a move that has changed the way Japan exports defense equipment, the Japanese government has recently relaxed its rules on defense equipment exports, allowing the country to supply Patriot missiles to the United States and 155mm artillery shells to the United Kingdom. The new rules allow Japan to supply equipment and weapons to countries that have granted Tokyo licenses to produce those weapons.

After receiving missiles from Japan to replenish its stockpile, the US could transfer them to Ukraine and European partners. However, the Japanese Foreign Ministry said the US must obtain Tokyo's consent before transferring missiles to a third country.

"The Japanese side has lost control over the weapons that Washington can now do whatever it wants with. It cannot be ruled out that Patriot missiles will be delivered to Ukraine under a tested plan. Such a development would be seen as a clearly hostile act against Russia and would lead to serious consequences for Japan in the context of bilateral relations," Zakharova said.

Also at the press conference, Ms. Zakharova reminded South Korea that it should not be surprised if Russia retaliates against Seoul's latest export restrictions.

Earlier this week, the South Korean Ministry of Trade, Industry and Energy added 682 types of goods to the list of goods subject to export control to Russia and Belarus from the beginning of 2024. According to TASS, these goods are believed to be able to be used for military purposes, including construction equipment, rechargeable batteries, aircraft parts, passenger cars, etc.

"This action will harm the economy and industry of South Korea itself. We reserve the right to take countermeasures and there is no need to be proportional," said a Russian Foreign Ministry spokesman.

South Korea and Japan did not immediately comment on Russia's new statement.