Former President Donald Trump is demanding that Intel’s new CEO, Lip-Bu Tan, resign immediately due to his alleged conflicts of interest.

“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 on Thursday. It was the first indication of what had prompted Trump’s call for Tan’s resignation.

Trump’s comments come in the wake of a letter sent on Tuesday by Republican Senator Tom Cotton to Intel’s board chair Frank Yeary, also expressing concern over the national security implications of Tan’s ties to China. Tan is a prolific investor in Chinese technology companies, a fact that Cotton noted in his letter, which he signed along with Republican Senator Marco Rubio.

Tan is a Silicon Valley veteran who has built a presence in semiconductors and venture capital over more than three decades. His investment firm is headquartered in San Francisco, but his business in Asia is centered in Hong Kong. From there, Tan’s firms have plowed millions of dollars into Chinese tech startups. Past investments have included Semiconductor Manufacturing International Corp (SMIC), which is China’s largest semiconductor manufacturer.

Tan’s track record is under increased scrutiny due to his former role as chief executive of Cadence Design Systems, a California-based firm that makes computer chip design software. Just last week, Cadence agreed to pay a fine after the U.S. accused it of violating export controls. Cadence had previously sold its chip design software to a Chinese university with close ties to the Chinese military. That revelation has raised fresh questions about Tan’s connections to the Chinese tech industry and how those will impact his new role at Intel.

Intel and the White House both declined to comment on Trump’s post. In the markets, Intel shares were down 3 percent in pre-market trading in New York on Thursday morning following Trump’s post.

Tan was only recently appointed CEO at Intel. He took over as CEO in March after the company’s board of directors ousted his predecessor, Pat Gelsinger, last December. As head of the company, Tan has a huge task on his hands. Intel has fallen behind in the global semiconductor race, struggling to keep up with Taiwan Semiconductor Manufacturing Company (TSMC), which dominates the industry.

Intel is the last U.S.-headquartered company capable of making advanced chips at scale. The Silicon Valley firm has been an industry powerhouse for decades. But Intel has missed the wave of the current boom in artificial intelligence chips, which are set to become the next battleground in the global competition for semiconductor supremacy.

Intel has received billions of dollars in government subsidies and loans to help it build a new facility in Ohio to begin manufacturing at scale. The new U.S. plant is part of a broader government-led push to bolster domestic semiconductor manufacturing capacity. The aim is to end the U.S.’s dependence on chipmakers from other countries, in particular those from Taiwan and South Korea. But Intel has fallen far behind TSMC in this regard, with its next-generation manufacturing technology years behind its rival. The situation has only put more pressure on Tan from day one.

In July, Tan warned that Intel needed a “significant external customer” for its 2-nanometer chipmaking technology, or else the company might have to stop development on it. If that were to happen, TSMC would in essence have a monopoly on next-generation chipmaking. The effects of that would be felt not only in the chip industry but in U.S. national security.

The stakes were on display as Tan launched a cost-cutting program to improve profitability at Intel. The efforts are designed to right Intel’s financial ship, but have also raised new concerns about the direction of the firm.

Senator Cotton’s letter to Intel’s board highlighted these concerns, which Cotton said were magnified by the company’s position as the recipient of taxpayer subsidies. “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,” Cotton wrote in the letter.