Elon Musk has told Tesla employees to come back into their respective offices at least 40 hours a week or leave the company.

Musk said in two separate emails that people must show up for at least 40 hours per week in a Tesla office. “If you don’t show up, we will assume you have resigned,” he said in one of the emails, first reported by Electrek and also obtained by CNBC.

“Anyone who wishes to do remote work must be in the office for a minimum (and I mean *minimum*) of 40 hours per week or depart Tesla,” Musk said in the first email, according to Electrek. “This is less than we ask of factory workers.”

“If there are particularly exceptional contributors for whom this is impossible, I will review and approve those exceptions directly,” the email continued.

“There are of course companies that don’t require this, but when was the last time they shipped a great new product? It’s been a while,” Musk wrote in the second email sent. He added that it’s important for senior employees to show their presence and said it’s why he “lived in the factory so much” and that, had he not, “Tesla would long ago have gone bankrupt.”

“Tesla has and will create and actually manufacture the most exciting and meaningful products of any company on Earth. This will not happen by phoning it in,” he added.

Responding to an inquiry about the leaked emails from a Twitter account known for promoting the CEO and Tesla, Musk said: “They should pretend to work somewhere else.