WASHINGTON (Reuters) - Despite threats of retaliation from China over U.S. plans to impose tariffs on up to $60 billion in Chinese goods, Treasury Secretary Steve Mnuchin on Sunday said President Donald Trump had no intention of backing down and was not worried about a trade war.

U.S. Treasury Secretary Steve Mnuchin attends a meeting at La Moneda Presidential Palace in Santiago, Chile March 21, 2018. REUTERS/Rodrigo Garrido

“We are going to proceed with our tariffs. We’re working on that,” Mnuchin told Fox News Sunday. “So, as President Trump said, we’re not afraid of a trade war, but that’s not our objective.”

Fears of a trade war between the United States and China have sent U.S. stock prices tumbling. The Dow Jones Industrial Average .DJI and the S&P 500 .SPX both lost nearly 6 percent by the end of last week.

A presidential memorandum signed by Trump last week will target up to $60 billion in Chinese goods with tariffs over what his administration says is misappropriation of U.S. intellectual property, but only after a 30-day consultation period that starts once a list is published.

Trump gave the Treasury Department 60 days to develop investment restrictions aimed at preventing Chinese-controlled companies and funds from acquiring U.S. firms with sensitive technologies.

Mnuchin said he believed the United States could reach an agreement with China on some issues, but said the tariffs would not be put on hold “unless we have an acceptable agreement that the president signs off on.”

China has urged the United States to “pull back from the brink” on the tariffs and threatened to retaliate by hitting U.S. agricultural exports.

Without giving a time frame, China’s commerce ministry said the government was considering a 25 percent tariff on U.S. pork. It did not announce potential tariffs on soy.

Republican Senator Joni Ernst of Iowa, a major exporter of farm products to China, said on the CBS program “Face the Nation” on Sunday that hers and other Midwestern states would be harmed by any retaliation.

Iowa is the top U.S. state for hog production. China imports more than a third of all U.S. soybeans.

“Nobody wins in a trade war,” she said. “So if they start retaliating, we will see significant impact - very detrimental impact not just in Iowa, but across the Midwest as well,” she said.