Ukraine imposed sanctions on three Chinese companies on Friday claiming they were involved in production of advanced Iskander missiles, a day after President Volodymyr Zelenskiy alleged that China had been supplying weapons to Russia.

China on Monday warned other countries against making trade deals with the United States to China’s detriment. Governments including those of Taiwan, Japan and South Korea have begun negotiations with Washington after President Donald Trump announced sweeping tariffs against almost all of America’s trading partners on April 2.

While Trump has expressed optimism about agreements with Europe and China, among others, so far it’s been just that: positive comments, but no signed deals.