Chinese Premier Li Qiang has appealed to Japanese Prime Minister Shigeru Ishiba for a joint response to recent tariff actions imposed by U.S. President Donald Trump, according to sources within the Japanese government.

The appeal was delivered through a formal letter sent via the Chinese embassy in Tokyo. In the message, Premier Li emphasized the importance of opposing protectionist trade policies and encouraged closer cooperation between Beijing and Tokyo to address the broader implications of the U.S. measures.

Officials from both countries’ foreign ministries have yet to comment on the communication.

The request follows heightened warnings from Beijing, which recently cautioned other nations against entering wide-ranging economic agreements with Washington that could disadvantage China. The appeal underscores growing concerns amid escalating trade tensions between the world’s two largest economies.

Japan, a longstanding U.S. ally, was among several nations affected by the latest round of U.S. tariffs. Tokyo has since initiated negotiations with Washington in an effort to resolve the issue. Diplomatic ties between China and Japan remain sensitive, shaped by a history of territorial disputes and economic rivalry.