AFP/APP – President Donald Trump was poised to unveil sanctions against China on Thursday for what he called the theft of US intellectual property, fueling fears of a trade war as Beijing vowed to retaliate.

White House spokesman Raj Shah told AFP that Trump will announce actions following an “investigation into China's state-led, market-distorting efforts to force, pressure, and steal US technologies and intellectual property.”

According to his schedule, released by the White House on Wednesday evening, he will sign “a Presidential Memorandum targeting China's economic aggression.”

The Chinese commerce ministry issued a pre-emptive warning, saying in a statement on Thursday that Beijing “will certainly take all necessary measures to resolutely defend its legitimate rights and interests”.

It is just weeks since Trump short-circuited White House deliberations and announced a raft of sanctions on foreign-produced steel and aluminum off the cuff.

That move prompted the resignation of top economic advisor Gary Cohn, a global stock market selloff, legal disputes and threats of retaliatory measures.

On Wednesday, Federal Reserve Chairman Jerome Powell warned that the prospect of a trade war was a growing threat to the world's largest economy.

Chinese Premier Li Keqiang urged Trump on Tuesday to not act “emotionally,” but the impulsive president is showing no sign of backing down.

US Trade Representative Robert Lighthizer recently put a separate proposed package of $30 billion in tariffs on Chinese imports on the president's desk.

And Trump appears to have agreed to at least that amount, as he tries to fulfil campaign promises to get tough on “cheating” by US trade partners, which he says have destroyed American jobs.

The US trade deficit with China ran to a record $375 billion last year — but US exports to the country were also at a record.

Washington has long accused Beijing of forcing US companies to turn over proprietary commercial information and intellectual property as a condition of operating in China.

Trump claims to have built up a generally good relationship with his Chinese counterpart Xi Jinping whom he has praised for his role in pressuring North Korea over its nuclear program.

However, the trade dispute threatens to cast a pall over those relations, especially given the recent warnings from Beijing.