Elon Musk is throwing down the gauntlet, demanding Tesla and SpaceX employees come in to the office at least 40 hours a week or quit.

The return to the office has been a challenging issue for many companies since the pandemic forced employees to work from home. Some companies have embraced remote work on a permanent basis, others have embraced varying degrees of hybrid work, and others are taking a hardline approach, demanding employees return to the office full-time. Count Musk in the latter category.

Internal Tech Emails tweeted copies of the emails Musk sent to employees.

“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 wrote to “ExecStaff,” with the subject line “Remote work is no longer acceptable.”

Musk reportedly sent a similar email to SpaceX employees.

Given how strongly many employees feel about continuing to work remotely, it’s a safe bet Tesla will be taking applications soon.