"Regarding the imposition of tariffs, China has repeatedly stated its position that trade and tariff wars have no winners and protectionism offers no way forward," foreign ministry spokeswoman Mao Ning said.

Trump said he would send the first tariff letters to various countries on Monday, days before his deadline for trading partners to reach a deal expires.

He said on Sunday he would send a first batch of up to 15 letters, warning that US levies on imports would snap back to the high levels he set in April if countries failed to make agreements.

And, in a post on his Truth Social network, he threatened a further 10 percent tariff on countries aligning themselves with the emerging BRICS nations, accusing them of "anti-Americanism" after they slammed his tariffs at a summit in Rio de Janeiro on Sunday.

Conceived two decades ago as a forum for fast-growing economies, BRICS has come to be seen as a Chinese-driven counterbalance to US and western European power.

However, Beijing defended the grouping on Monday as "an important platform for cooperation between emerging markets and developing countries".

"It advocates openness, inclusivity and win-win cooperation," Mao said.

"It does not engage in camp confrontation and is not targeted at any country," she said.