Earlier, Chinese Foreign Ministry spokesman Lu Kang said China was ready to act, though he did not confirm the start date for Chinese tariffs.
"Russia claims the United States duties of 25% and 10% on imports of steel and aluminum products respectively are inconsistent with provisions of the WTO's General Agreement on Tariffs and Trade (GATT) 1994 and the Agreement on Safeguards", the WTO press service reports.
"We agree with nearly all the complaints the USA has against China, it's just we don't agree with how the United States is handling it", another diplomat said.
Chinese state media has promoted the message that the European Union is on China's side, officials said, putting the bloc in a delicate position.
It shows the depth of Chinese concern about a trade war with Washington, as Trump is set to impose tariffs on billions of dollars worth of Chinese imports on July 6.
"The Chinese government's position has been stated many times".
Trump also said on Sunday that the EU was "as bad" as China when it came to the way European countries traded with the US.
That's right: The President of the United States just issued a big fat FART act.
"The US has maintained hegemony in the military and financial fields for many decades. Now it is pursuing economic hegemony", the English-language newspaper said in an editorial.
"It has frequently waged wars against other sovereign countries and made use of the dominant influence of the United States dollar in the global markets to fleece other countries".
Australia won't escape fallout if the USA and China fall into a trade war.
China has vowed to retaliate in kind with its own tariffs on US agricultural products and other goods and to take more "qualitative" measures if Trump escalates the conflict.
According to the report, the Chinese authorities will allow its tariffs against USA products to go into effect starting at 12 a.m. Friday. "The trick here is to get the other allies on side with us, as opposed to having a trade war with them as well, to basically clobber the Chinese on trade".