Republican presidential front-runner Donald Trump has accused China of "raping" the US, in renewed criticism of China's trade policy.
He told a rally in Indiana that China was responsible for "the greatest theft in the history of the world".
Mr Trump, a billionaire businessman, has long accused China of manipulating its currency to make its exports more competitive globally.
This, he says, has badly damaged US businesses and workers.
"We can't continue to allow China to rape our country, and that's what we're doing," he told the campaign rally on Sunday.
"We're going to turn it around, and we have the cards, don't forget it," he added. "We have a lot of power with China."
Premier Li Keqiang has said the US election "has been lively and has caught the eye", but many in China see it as more than that.
They consider the flamboyant New York billionaire an inspiration rather than an antagonist.
In his campaign manifesto, Mr Trump pledges to "cut a better deal with China that helps American businesses and workers compete".
He sets out four goals that include immediately declaring China "a currency manipulator" and putting "an end to China's illegal export subsidies and lax labour and environmental standards".
Latest figures from the US government show the trade deficit with China reached an all-time high of $365.7bn (£250.1bn) last year. By February this year it had already reached $57bn.
This is the first time Mr Trump has used the word "rape" in the context of China and trade, but his campaign has been punctuated by inflammatory comments.
He was confronted by hundreds of protesters in California on Friday before giving a speech to the state's Republican convention. Mr Trump was forced to enter the building by the back entrance.
Protesters were angry at his views on immigration: he has advocated building a border wall with Mexico, and has also referred to Mexicans as "rapists" and criminals responsible for bringing illegal drugs into the US.
Anti-Trump protesters were also out in force during the annual May Day rallies in California.
Donald Trump was the focus of anger for some at the May Day protest in Los Angeles on Sunday
The Trump campaign had to cancel several rallies in March after hundreds of protesters threatened to disrupt events in Chicago and St Louis.
Mr Trump has called himself the Republican "presumptive nominee" after a string of primary wins.
In terms of delegate support, the property tycoon is far ahead of his nearest rivals, Texas Senator Ted Cruz and John Kasich, the governor of Ohio.
On the other side of the race, Hillary Clinton is expected to beat Bernie Sanders to the Democratic nomination and fight for the presidency in November's general election.