AFP, BEIJING: China warned yesterday that it was ready to hit back if the United States damaged its economic interests, fuelling fears of a trade war after President Donald Trump unveiled tariffs on steel and aluminium.

Trump's announcement on Thursday sparked a flurry of counter-threats from other nations. But Washington's main trade rival had avoided any overt warnings of potential retaliation until now.

"China doesn't want a trade war with the United States," Zhang Yesui, spokesman for the National People's Congress, told a news conference on Sunday, the eve of the rubber-stamp parliament's annual session.

"But if the US takes actions that hurt Chinese interests, China will not sit idly by," Zhang said. An official English-language interpreter added the phrase, "and will take necessary measures".

Zhang warned that "policies informed by misjudgement or wrong perceptions will hurt relations and bring consequences no side wants to see".