(Reuters) – Tesla (NASDAQ:) Inc Chief executive Elon Musk asked his employees to either return to work or to leave, according to a memo that was circulated on social media.

According to the memo, “Anyone who desires remote work must remain in the office at least 40 hours per semaine or they will leave Tesla.”

Reuters was unable to verify that the memo is authentic. Tesla has not responded to my request for comment. Musk couldn’t be reached for comment.

A billionaire proposed that he take responsibility for the response to the message tweeted by an unknown account. Twitter Inc (NYSE: ) In a deal worth $44 billion, he said that they should “pretend to be working somewhere else.”

Musk, the memo stated that he would approve any case where the minimum was not met.

Tesla is joining a growing number of businesses that require employees to return to work. Although some large companies have adopted permanent work-from-home policies, other businesses such as Alphabet Inc and Google think it best to promote in-person interactions between colleagues.

Parag Agrawal, CEO of Twitter, tweeted March 3rd that Twitter offices were reopening. However employees can still work remotely if necessary.

Agrawal tweeted, “Wherever I feel most productive is where I will work,” https:// on March 3.