A top White House aide said President Trump's threat to hit $150 billion worth of Chinese goods with tariffs is sending a message to China that Trump will stand up to China until it improves its exploitive trade practices that have cost America tens of thousands of jobs.

"This is business, and this is the kind of business where we have to stand firm against China's unfair trade practices, unlike the previous presidents who the for last 16 years prior to this president basically surrendered over 70,000 factories to China and millions of manufacturing jobs," said Peter Navarro, White House director of trade and industrial policy.

Navarro said on Fox News that while Trump initially threatened tariffs on $50 billion worth of Chinese goods, but is now mulling $150 billion after China responded with proposed tariffs of its own against the U.S., including on key U.S. agriculture exports.

But Navarro said the White House was ready for that reaction, which is why Trump asked Agriculture Secretary Sonny Perdue to come up with a plan to help U.S. farmers. U.S. soybean growers in particular are threatened by China's move.

"First, he will have the backs of American farmers when China tries to attack them," Navarro said. "He's directed the secretary of Agriculture, Sonny Perdue, a great American, to implement a plan immediately to prevent any harm done to our American farmers. And we want to assure you that that plan will be put in place immediately."

Navarro said Trump's moves are sending a "very clear message to China" that he will "stand up for America."

He added that Trump will work with other countries to help put pressure on China to stop its theft of intellectual property, and its policy of forcing companies to manufacture within China in order to have access to its market.

"Everybody in the world knows China is doing this," he said. "Nobody's had the courage but Donald Trump to stand up to it."