China’s government on Thursday warned “there is no winner in a trade war” after an aide to President Donald Trump called in published comments for a tougher stance toward Beijing.

A foreign ministry spokeswoman, Hua Chunying, appealed for dialogue to preserve stable relations when asked about the comments by Trump’s chief strategist, Steve Bannon.

In comments to The American Prospect posted online, Bannon said the United States is in an “economic war” with China. He recommended pursuing a trade investigation of Beijing’s technology policies and anti-dumping action over Chinese exports of steel and aluminum.

“There is no winner in a trade war,” Hua said at a regular news briefing. “We hope the relevant people can refrain from dealing with a problem in the 21st century with a zero-sum mentality from the 19th or the 20th century.”

Hua appealed for dialogue to “preserve the sound and steady growth of China-U.S. relations.”

On Monday, Trump instructed U.S. trade officials to look into whether to launch a formal investigation into whether Beijing improperly requires foreign companies to hand over technology as a condition of market access.

The Chinese government criticized that as a violation of the spirit of global trade rules. It warned it will take “all appropriate measures” if Chinese companies are hurt.