STORY: Biden was asked at a news conference whether he thought Musk was a threat to national security and if his acquisition of Twitter with help from a Saudi Arabian conglomerate should be investigated by the U.S. government.
"I think that Elon Musk's cooperation and or technical relationships with other countries is worthy of being looked at," Biden said.
"Whether he is doing anything inappropriate, I'm not suggesting that. I'm suggesting they're worth being looked at."
Musk's purchase of Twitter sparked concerns his companies, such as electric carmaker Tesla, could face pressure from countries trying to control online speech. The world's richest man, is CEO of Tesla and rocket company SpaceX, among others.