Donald Trump has called for the resignation of Intel CEO Lip-Bu Tan, alleging that the new leader of the U.S. chip giant is “highly conflicted.”

“The CEO of INTEL is highly CONFLICTED and must resign, immediately. There is no other solution to this problem,” Trump wrote in a post on the Truth Social platform Thursday morning.

Trump’s post came after Sen. Tom Cotton sent a letter to Intel’s board chairman Frank Yeary expressing “concern about the security and integrity of Intel’s operations” due to Tan’s business relationships in China.

Intel CEO Tan is a prolific investor in Chinese technology companies, including as a founding investor in Semiconductor Manufacturing International Corp (SMIC), China’s largest chipmaker.

Cotton expressed concern in his letter over Tan’s connections to China, adding that “Intel is the most important advanced semiconductor manufacturer in the United States.”

Intel and the White House declined to comment on Trump’s post.

Tan’s appointment as Intel CEO has drawn scrutiny from both sides of the aisle. Last week, Trump’s press secretary Karine Jean-Pierre told reporters that Tan’s business ties to China would “raise a lot of questions in the minds of a lot of people.”

Sen. Cotton’s letter, dated Thursday, added to criticism over Tan’s business relationships in China. “Intel is required to be a responsible steward of American taxpayer dollars and to comply with applicable security regulations,” Cotton wrote. “Mr Tan’s associations raise questions about Intel’s ability to fulfill these obligations.”

Tan has also been criticized for his past leadership at Cadence Design Systems, a California-based software company. Cadence disclosed earlier this month that it violated U.S. export controls by providing chip design tools to Fudan University in China, which has military ties. Tan is a Cadence board member.

Tan is a Silicon Valley veteran with a decades-long track record of building semiconductor and venture capital firms. He runs a San Francisco-based investment firm, based in Hong Kong, and has invested in numerous Chinese technology companies. SMIC was one of his early investments.

Intel shares fell 3 percent in pre-market trade in New York Thursday morning after Trump’s post.

Tan, who has been Intel’s CEO since March, replaced Pat Gelsinger, who the company’s board ousted in December. Tan’s leadership is being closely watched as Intel, the Silicon Valley icon, has struggled to catch up to TSMC, the world’s largest chipmaker.

Intel, the largest U.S. chipmaker by market cap, has been at a crossroads in the global chip race. The company is the only U.S.-headquartered firm still capable of manufacturing advanced semiconductors. But even with that in mind, Intel has mostly missed out on the current boom in artificial intelligence chips.

To stay competitive, Intel has received billions in government subsidies and loans. The funding is part of the Biden administration’s push to expand domestic chip manufacturing and wean the United States off foreign chipmakers in Taiwan and South Korea. But Intel has lagged TSMC in advanced manufacturing, placing pressure on Tan from the beginning.

In July, Tan warned that Intel may be forced to stop developing its next-generation chipmaking technology if the company fails to land a “significant external customer.”

The move would give TSMC a virtual monopoly over leading-edge chipmaking, and could have major implications not only for the semiconductor industry but for U.S. national security.