The Trump administration raised duties on $200 billion of Chinese imports to 25% from 10%. China's Commerce Ministry said it would impose "necessary countermeasures" but gave no details.

The increase went ahead even after American and Chinese negotiators began more talks in Washington aimed at ending a dispute that has disrupted billions of dollars in trade and shaken global financial markets.

"The risk of a complete breakdown in trade talks has certainly increased," said Michael Taylor of Moody's Investors Service in a report.

American officials accuse Beijing of backtracking on commitments made in earlier rounds of negotiations.

The talks were due to resume Friday after wrapping up Thursday evening with no word on progress.

"China deeply regrets that it will have to take necessary countermeasures," said a Commerce Ministry statement.