The United States threatened to impose tariffs on $50 billion of imports from China unless Beijing addressed the issue of theft of American intellectual property.

This declaration came after the two sides had agreed earlier this month to look at steps to narrow China's $375 billion trade surplus with America.

Fears of a trade war between the world's two biggest economies had receded after the administration of President Donald Trump had reached a deal that would put ZTE Corp back in business after banning China's second-biggest telecoms equipment maker from buying US technology parts.

Still hanging in the balance, however, is San Diego-based Qualcomm Inc's proposal to acquire NXP Semiconductors NV - a $44 billion deal that requires clearance from China's antitrust regulators.

The recent easing in tensions had fueled optimism that an agreement was imminent.