Donald Trump has called on Intel CEO Lip-Bu Tan to step down from the chip giant’s board, claiming the veteran semiconductor executive is “highly conflicted.”

The former U.S. president posted on Truth Social on Thursday: “The CEO of INTEL is highly CONFLICTED and must resign, immediately. There is no other solution to this problem.”

The remarks were made without further elaboration on what aspects of Tan’s background and business relationships Trump believes to be conflicted. They follow in the footsteps of U.S. Senator Tom Cotton, who wrote a letter to Intel’s board chair Frank Yeary earlier this week, warning that Tan’s business relationships with China could represent “a conflict of interest and a potential risk to national security.”

Cotton cited Tan’s history of investing in Chinese companies while serving as a “pioneering tech investor and serial entrepreneur with deep roots in both Silicon Valley and China.” In particular, he pointed to Tan’s role in raising capital for Chinese technology companies, including through a venture capital firm he leads based in San Francisco, as well as companies in Hong Kong.

Tan has also invested in China’s largest chipmaker, Semiconductor Manufacturing International Corp (SMIC), although he sold his stake in the company earlier this year after SMIC was placed on the U.S. government’s trade blacklist.

Tan’s record as an investor and executive has come under further scrutiny over the past week for his prior position as CEO of Cadence Design Systems, a California-based firm that makes software for designing semiconductor chips.

Cadence recently admitted to having violated U.S. export controls when it sold one of its chip design software packages to a Chinese university that has reportedly had “significant ties to the Chinese military.” This has raised questions about Tan’s network and track record, with Senator Cotton arguing that Intel’s board must consider “whether Mr Tan’s extensive ties to the Chinese government and technology sector are a fit and proper matter for Intel and the American people.”

Intel has declined to comment on Trump’s statement, as has the White House. However, Intel’s stock price was down 3 percent in pre-market trading on Thursday morning in New York following the Trump post.

Tan was appointed Intel’s new CEO in March after the company’s board forced the resignation of his predecessor, Pat Gelsinger, in December. He faces a significant challenge in turning Intel around, as it has so far missed out on the boom in AI chips and trails Taiwan Semiconductor Manufacturing Company (TSMC) in its manufacturing technology.

Intel’s position as the last U.S.-headquartered advanced chipmaker has not been enough to ensure its success in the rapidly changing world of chips. Despite receiving billions of dollars in government subsidies and loans, Intel has been left behind in the transition to artificial intelligence, in which chipmaking is being seen as the new battleground.

Intel may receive more financial support from the government if it can convince lawmakers and national security officials that Tan can be trusted to run the firm as the U.S. government increasingly sees semiconductor manufacturing as a matter of national security. However, in a sign of the pressure on Tan to change course, Intel warned that it might be forced to stop developing its leading-edge chipmaking process unless it secured a “significant external customer” for the technology in July.

Cotton raised the alarm at this, writing: “Intel is required to be a responsible steward of American taxpayer dollars and to comply with applicable security regulations. Mr Tan’s associations raise questions about Intel’s ability to fulfill these obligations.”

Intel’s current struggles have also been compounded by Tan’s moves to cut costs, with an estimated $3 billion in cost-cutting planned. While such moves are viewed by some as necessary to restore Intel’s fortunes, others are concerned about Intel’s future direction.