(Bloomberg) -- Republican lawmakers accused a Chinese auto-parts maker of a “blatant” effort to evade US tariffs in the latest sign of rising pressure in Washington to limit China’s growing presence in the car business.

Calling the alleged violations a threat to national security, the legislators demanded Department of Homeland Security Secretary Alejandro Mayorkas investigate Qingdao Sunsong Co. Ltd. for routing shipments of rubber-hose products through Thailand to evade 25% tariffs imposed on its US unit. 

“Reviews of Qingdao Sunsong’s public disclosures lay out a case of blatant trade fraud that is having a catastrophic impact on American manufacturers,” China Select Committee Chairman Mike Gallagher and committee member Representative Darin LaHood wrote in a letter Thursday. 

“One American company has been compelled to accumulate significant debt, divest itself of two business divisions and most recently lay off one-quarter of its workforce due to Sunsong’s trade fraud,” they wrote, without identifying the US firm. 

The lawmakers’ letter adds to a drumbeat from Republicans on Capitol Hill raising concerns about China’s auto industry. GOP lawmakers are probing Ford Motor Co.’s joint venture with Chinese battery maker Contemporary Amperex Technology Co. Ltd., which they say is an attempt by CATL to take advantage of tax credits in the Inflation Reduction Act, President Joe Biden’s signature climate policy. 

Read more: China’s Stranglehold on EV Supply Chain Will Be Tough to Break

Ford paused construction on that plant this week, citing “a variety of considerations” without elaborating. Gallagher called Ford’s move “a crucial first step to reevaluate its deal with Chinese Communist Party-aligned EV battery firm.” 

The United Auto Workers, meanwhile, blasted the pause as a “barely-veiled threat” to cut jobs during their ongoing strike against the Big Three automakers. Ford is throttling back on ambitious electric vehicle production plans as sales growth slows due to consumer resistance to the high price of battery-powered models.

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