President Donald Trump has called for the immediate resignation of Intel’s new chief executive, Lip-Bu Tan, over the “highly conflicted” veteran semiconductor industry veteran.

Trump’s demand, posted on his Truth Social network on Thursday, was brief. “The CEO of INTEL is highly CONFLICTED and must resign, immediately. There is no other solution to this problem,” he said, without elaborating.

Trump’s comment came on the same day that Republican Senator Tom Cotton sent a letter to Intel board chair Frank Yeary to express his “concern about the security and integrity of Intel’s operations” due to the investor’s long business connections to China. Cotton cited Tan’s prolific track record of investing in Chinese technology companies, pointing to a risk of national security conflicts as Intel is the U.S.’s leading advanced chipmaker.

Tan, a well-known Silicon Valley entrepreneur, has worked for decades in semiconductors and venture capital, building a reputation as a global investor and chip industry executive. He is best known for his San Francisco-based investment firm, based in San Francisco, as well as an affiliated Hong Kong-listed company, which has made many investments in Chinese technology companies. One of his most famous previous investments is SMIC, the largest chipmaker in China.

Tan’s past performance has also been under closer scrutiny following his previous role as CEO of Cadence Design Systems, another U.S. chip industry company headquartered in California. Cadence, which makes software for designing chips, admitted last week that it had violated U.S. export controls by selling its chip design software to a Chinese university that is reportedly affiliated with the Chinese military. The announcement came as Cadence reported first-quarter results that missed Wall Street estimates. Cadence’s stock has plunged 30 percent since the disclosure of the breach.

Intel and the White House did not immediately respond to requests for comment on Trump’s comment. Intel’s share price dropped 3 percent in pre-market trading in New York on Thursday after Trump’s post.

Tan was appointed CEO of Intel in March, after the company’s board decided to remove his predecessor Pat Gelsinger last December. Tan has faced an uphill battle since he assumed his current position as CEO at the struggling Silicon Valley firm. Intel, once the world’s leading semiconductor manufacturer, has lost significant ground to Taiwan Semiconductor Manufacturing Company (TSMC) in recent years.

Intel is in an odd position in the chip industry. On the one hand, it is still the only company headquartered in the United States that can make advanced semiconductors. On the other hand, the company has largely missed the recent boom in artificial intelligence chips, which are seen as the next arena of global competition for chipmakers.

Intel has received billions of dollars in government subsidies and loans to improve its competitiveness, including from the White House and the Department of Defense. The semiconductor industry has been given billions of dollars in government loans and subsidies as part of Washington’s effort to boost domestic semiconductor production and reduce U.S. dependence on foreign chipmakers, especially those in Taiwan and South Korea. But even with this support, Intel lags far behind TSMC, the world’s largest contract chipmaker, in terms of cutting-edge manufacturing capabilities. As a result, the pressure has been on Tan to turn Intel around from day one.

Tan made a dramatic statement last month, warning that if Intel does not find a “significant external customer” for its next-generation chipmaking technology, the company will likely stop developing it. If Intel were to pull the plug, TSMC would have a monopoly on leading-edge chip production, with serious consequences for both the semiconductor industry and U.S. national security.

Uncertainty over Intel’s next-generation technology has come at the same time as Tan’s cost-cutting drive in an effort to turn the Silicon Valley company’s fortunes around. The strategy is designed to restore Intel’s profits, which are valued by some investors, but it has added to the general sense of malaise about Intel’s long-term prospects.

Senator Cotton’s letter to the Intel board is part of a broader review of the terms of Intel’s government support. “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.”