President Joe Biden said Twitter owner and Tesla CEO Elon Musk’s relationship with other countries was “worthy of being looked at,” but declined to say how that could be done, CNN transmits.

“I think that Elon Musk’s cooperation and/or technical relationships with other countries is worthy of being looked at, whether or not he is doing anything inappropriate,” Biden said, when asked if Musk was a threat to national security. “But that’s all I’ll say.”

When a reporter in the room asked, “How?” the President responded: “There’s a lot of ways.”

Just before Musk completed his $44-billion acquisition, Bloomberg reported that Biden administration officials were in early discussions about possibly subjecting some of Musk’s ventures to national security reviews, including the Twitter takeover. Asked by CNN at the time, the administration pushed back on the report, which cited people familiar with the matter.

“We do not know of any such conversations,” National Security Council Spokesperson Adrienne Watson said in a statement. A Treasury spokesperson said the Committee on Foreign Investment in the United States “does not publicly comment on transactions that it may or may not be reviewing” by law and practice.

Among the equity investors who committed to provide financing to help Musk fund the deal are several foreign entities, including the Qatar sovereign wealth fund and Saudi Arabian Prince Alwaleed bin Talal, who was already one of Twitter’s largest investors prior to Musk’s proposed takeover.