The new owner of Twitter, Elon Musk, gave employees until Thursday evening to commit to working or leave the company, according to a copy of a late-night internal email sent by the billionaire and obtained by CNN.

Musk also wrote in the memo: "Moving forward, to build Twitter 2.0 breakthrough and succeed in an increasingly competitive world, we will need to be extremely rigorous. This means working long hours at high intensity, only exceptional performance will determine the degree of success."

In the memo, Musk continues to explain how Twitter will be "more engineering-driven" and then gives employees a warning: "If you are sure you want to be part of the new Twitter, please click yes on the link below," directing employees to what appears to be an online form. Musk also said that any employee who does not do so by 5 pm Thursday will receive a three-month severance.

Also, the email, which has the subject "Crossroads," comes at a time when Musk has publicly and secretly clashed with Twitter employees over his approach to managing the company. It also comes after Musk fired senior Twitter executives, dissolved the board, and laid off nearly half of the staff.

Additionally, Musk stated in the memo: "Whatever decision you make, we thank you for your efforts to make Twitter successful."