President Joe Biden says that Elon Musk’s dealings with countries outside of the United States are “worthy of being looked at.” Speaking to reporters, Biden didn’t elaborate on if some kind of of investigation was underway, but suggested the Tesla and Twitter CEO deserved further scrutiny.

“I think that Elon musk’s cooperation and/or technical relationships with other countries is worthy of being looked at,” Biden said. “Whether or not he is doing anything inappropriate – I’m not suggesting that. I’m suggesting it’s worth being looked at, and that’s all I’ll say.”

It’s unclear exactly which of Musk’s relationships Biden was referring to, but he’s not the first official to raise Musk’s ties to other countries as a potential concern. Senator Chris Murphy has said the Committee on Foreign Investment in the US (CFIUS) should investigate the “national security implications” of Musk’s deal to buy the company. Murphy and others have pointed to major investments from Saudi Arabia and Qatar.

Other critics have noted that Tesla’s business dealings in China could make it difficult for Musk to make content decisions that affect the country, or that government officials could pressure him to turn over data. The Washington Post reported in June that “some U.S. intelligence analysts and White House officials are among those concerned about the potential for arm-twisting by China if Musk gets hold of Twitter.”

Musk was also widely criticized for tweets suggesting that “the will of the people” should decide whether parts of Ukraine taken over by Russia should become part of Russia. He later threatened to stop paying for Starlink internet for the Ukrainian government, but later walked back the comments.