Beijing: China vowed on Friday to "immediately" retaliate to US tariffs as Washington moved closer to imposing duties that could trigger a trade war.

"If the US side adopts unilateral protectionist measures and damages China's interests, we will immediately react and take necessary measures to firmly safeguard our legitimate rights and interests," said foreign ministry spokesman Geng Shuang during a regular news briefing.

US President Donald Trump is due to unveil later on Friday a final list of Chinese imports that would face punishing tariffs, though the administration has not yet publicly said when the measures will be imposed.