Republican presidential nomination front-runner Donald Trump has accused China of "raping" the US with their trade policy.

At a rally in Indiana the celebrity businessman said China manipulates its currency to keep its exports cheap. Trump says this 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... We have a lot of power with China."

In his campaign manifesto Trump pledged to "cut a better deal with China that helps American businesses and workers compete".

Last year US government financial data showed the trade deficit with China reached an all-time high of $365.7 billion.

The Chinese government has not yet responded to Mr Trump's comments.