The Twitter logo is displayed on the exterior of Twitter headquarters on October 26, 2022 in San Francisco, California.The Twitter logo is displayed on the exterior of Twitter headquarters on October 26, 2022 in San Francisco, California.

According to internal emails obtained by CNBC, engineering staff at the San Francisco headquarters have been called into the office by new owner and CEO Musk.

A companywide email was sent out late on Thursday stating that the offices would be closed from Friday until Monday and that badges would not be allowed.

In a pair of widely distributed emails sent at the start of business on Friday, Musk called for "anyone who actually writes software" to report to the headquarters by Friday afternoon. He asked them to give him a high-level report of the best code they have worked on.

He encouraged people to fly to San Francisco to present in person after initially calling for engineers to come into the office. He stated in an email that he would be working late into the night at the company's headquarters office on Friday and Saturday.

Musk wants to do short, technical interviews that will help him better understand the Twitter tech stack.

Those authorized to work remotely can ask to speak with Musk via video. Only those who can't get to the office or have a family emergency are excused.

There are conflicting messages on returning to the office after a wave of resignations.

Their new Chief Twit, as Musk jokingly calls himself, had issued an ultimatum a day earlier telling them they would need to commit to his vision, and agree to work "long hours at high intensity."

The three employees who resigned told CNBC they still had access to the internal systems.

It may take a long time for the company to figure out who should have access to email and other systems after so many people quit or were laid off.

The people asked not to be named due to fear of repercussions.