Republican presidential front-runner Donald Trump ratcheted up his rhetoric against Chinese trade policy Sunday night, saying "we can't continue to allow China to rape our country."

Trump has long accused China of manipulating its currency to boost the country's exports. However, his remarks in Fort Wayne, Ind., Sunday mark a graphic escalation in his language. While he's compared the policy to sexual assault before, this is the first time he's done so as a presidential candidate.

The real estate mogul also called the U.S. the "the piggy bank that's being robbed" as a result of its trade deficit with China, which reached an all-time high of $365.7 billion at the end of last year. The trade deficit measures the value of American goods exported to China, as well as the value of goods imported from China.

Trump's comments are certain to stir controversy following his claim that Democratic front-runner Hillary Clinton's success is dependent on her gender. 

“The only card she has is the woman card,” Trump told “Fox News Sunday.” “Even women don’t like her. If she were not a woman, she would not even be in this race.”

While both Clinton and Trump’s favorability ratings among women are low, Trump’s are worse, especially among female general election voters.

However, Trump argued Sunday that his numbers will improve if and when he faces Clinton in the general election.

“Once I start on Hillary, the numbers will change,” he said. “Watch what happens with Hillary. Watch what happens with her numbers.”

Trump was speaking two days ahead of the Republican primary in Indiana, where the latest polls show him holding a double-digit lead over Texas Sen. Ted Cruz. At a rally in La Porte Sunday night, Cruz urged Indiana voters to help him deny Trump the 1,237 delegates needed to secure the nomination prior to the Republican convention.

"I believe in the men and women gathered here and the goodness of the American people that we will not give into evil," Cruz said at one point.  "All across this country, millions of Americans right now are praying for you. You’re being lifted up in prayer right now."

Any solemnity the occasion had was interrupted by a young boy who heckled Cruz repeatedly, including with the phrase, "You suck!"

"One of the things that hopefully someone has told you is that children should actually speak with respect,” Cruz said as police escorted the boy out. "Imagine what a different world it would be if someone had told Donald Trump that years ago."

Fox News' Dan Gallo contributed to this report.