Illumina (ILMN) stock plunged more than 5% in pre-market trading on Tuesday, as the gene sequencing equipment maker found itself caught in the crosshairs of the ongoing trade war between the United States and China.

Beijing announced a ban on imports of Illumina's gene sequencers to China, just minutes after President Donald Trump's additional 10% tariff on Chinese goods took effect. This move came after China had previously added Illumina to its "unreliable entity" list in February, prohibiting the company from exporting or importing in China or making new investments in the country.

The commerce ministry stated that Illumina had violated market principles and discriminated against Chinese enterprises, seriously harming their interests. As a result, the "unreliable entity" list working mechanism decided to prohibit Illumina from exporting gene sequencers to China, which accounts for approximately 7% of the company's sales.