Jim Young/Reuters

Soybeans were down more than 2% Tuesday.

China promised to retaliate if the Trump administration imposed additional tariffs on the country.

Follow soybeans in real time here.

Soybeans tumbled Tuesday after President Donald Trump threatened additional tariffs on the world's largest soy importer, raising concerns that retaliatory levies could further target American agricultural products.

Soybeans were down 2.20% to $8.86 a bushel at 9:15 a.m. ET. Prices have fallen nearly 8% over the last week as import taxes get slapped on the legume.

Trump said Monday his administration could impose additional tariffs on $200 billion worth of Chinese goods and warned that if Beijing retaliated, another $200 billion could be targeted. That, plus tariffs imposed last week, would affect $450 billion worth of Chinese products — an amount approaching its total exports to the US of $505 billion in goods.

The move marks the latest round of escalations in a trade fight that has dragged on for months. The Trump administration said Friday it would move forward with 25% tariffs on $50 billion worth of Chinese goods, despite ongoing trade negotiations between Beijing and Washington. Chinese officials quickly pushed back, imposing on the US dollar-for-dollar retaliatory tariffs on 545 categories of US products, including soybeans.

Beijing promised on Tuesday to hit back again. While matching Washington dollar-for-dollar on tariffs seems out of reach — since the US imported $130 billion in Chinese goods last year — the Chinese Commerce Ministry said they would "launch comprehensive measures that match the US move in quantity and quality."

In Iowa, a top exporter of soybeans, the prospect of additional hits to the agricultural sector has farmers increasingly nervous. The Des Moines Register's Donnelle Eller reports that one University of Iowa economist estimates China's current tariffs on US soybeans could cost farmers in the state up to $624 million.

And China isn't the only major importer the US soybean industry has to worry about. Reuters reported last week that Mexican officials are mulling imposing tariffs on $4 billion worth of US imports of corn and soybeans. That's after Trump hit the EU, Mexico, and Canada, with hefty levies on steel and aluminum imports.

Soybeans have shed nearly 12% since March, when the Trump administration announced plans to penalize China for what US officials found in an investigation were "unfair" trade practices, including intellectual property theft.

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