Donald Trump has called on the new Intel chief executive, Lip-Bu Tan, to resign, saying the veteran chip industry executive is “highly conflicted.”

In a post on Truth Social on Thursday, Trump claimed: “The CEO of INTEL is highly CONFLICTED and must resign, immediately. There is no other solution to this problem.” No further details were provided in the post about Tan’s purported conflicts of interest.

The statement is the latest development in a controversy around Tan’s appointment that has unfolded over the past week. Last week, Republican Senator Tom Cotton sent a letter to Intel’s board chairman Frank Yeary questioning the “security and integrity of Intel’s operations” in light of Tan’s extensive business connections to China. “Mr Tan has a long history of being a prolific investor in Chinese technology companies, including the world’s largest chip maker, which raises national security concerns,” Cotton wrote.

Tan, a Silicon Valley veteran who has been active in the semiconductor and venture capital industries for decades, has poured millions of dollars into Chinese technology companies through his San Francisco-based investment firm and a separate Hong Kong-based company he also chairs. Past investments have included Semiconductor Manufacturing International Corp (SMIC), China’s largest chipmaker.

Tan has also faced increased scrutiny for his past leadership of Cadence Design Systems, a California-based firm that makes software for designing computer chips. Last week, Cadence conceded it had violated U.S. export controls after it sold its chip design software to a Chinese university with close military ties. The disclosure has led some to question Tan’s business ties and past investments, given that the Chinese university buying the chip design tools has a “business cooperation” agreement with SMIC.

Intel and the White House declined to comment on Trump’s comments. The company’s shares were down 3 percent in pre-market trading in New York on Thursday in the wake of Trump’s statement.

Tan replaced Gelsinger as Intel’s CEO in March after the company’s board fired the previous CEO, Pat Gelsinger, in December. Gelsinger was forced out just months after taking over as Intel’s CEO in a controversial decision, which Intel has said was made after Gelsinger broke his employment contract.

Tan’s appointment comes at a time of immense pressure for Intel. The company has lost ground to Taiwan Semiconductor Manufacturing Company (TSMC) in recent years and has failed to break into the artificial intelligence chip market, which is the new focal point of the global chip race. Intel has been awarded billions of dollars in subsidies and loans in recent months in an effort to support its U.S. manufacturing. The federal funding is part of a wider effort by the Biden administration to increase domestic semiconductor production and lower U.S. reliance on overseas chipmakers. But with Intel far behind TSMC in advanced chipmaking, the pressure on Tan to perform has been intense from the start.

In July, Tan warned the company would have to “evaluate whether we stop developing” its next generation of chipmaking technology if it failed to find a “significant external customer” for the manufacturing tool. If Intel were to give up on next-generation manufacturing, TSMC would have a de facto monopoly in advanced chipmaking. Such a scenario would have serious repercussions not only for the semiconductor industry but also for U.S. national security.

The uncertainty surrounding Intel’s future has played out against Tan’s push to cut costs and boost profitability. While welcomed by some investors, the moves have added to broader concerns about Intel’s long-term trajectory.

In his letter, Senator Cotton focused on Intel’s unique status as the recipient of large government subsidies. “Intel is required to be a responsible steward of American taxpayer dollars and to comply with applicable security regulations,” he wrote. “Mr Tan’s associations raise questions about Intel’s ability to fulfill these obligations.”

Tan’s investment and leadership history put Intel’s board in a difficult position. On the one hand, Tan’s decades of experience in the industry and his connections in Asia may be seen as a positive in an industry where U.S. companies rely heavily on foreign talent and markets. But his past ties to Chinese firms and Cadence’s recent export control violation have provided critics an opening to argue Tan is a liability for Intel at a time of increasing U.S. competition with Beijing in advanced technologies.