Read the 2:30 a.m. email Elon Musk sent to staff, his first, announcing the end of remote working at Twitter

• Elon Musk has put an end to remote working at Twitter.
• Musk emailed staff to tell them to return to the office for at least 40 hours a week.
• He also warned staff in the email that "the road ahead is arduous."

Elon Musk on Wednesday announced the end of remote working at Twitter.

Musk, who took over Twitter on October 27, sent an email to his employees for the first time on Wednesday. The email was sent  2:39 a.m. ET, according to a timestamp on the email reviewed by Insider.

The billionaire wrote in the email that employees would no longer be permitted to work remotely. Twitter expected staff to be in the office for at least 40 hours a week unless Musk gave approval for them to work elsewhere, according to the email.

Musk told Twitter employees "the road ahead is arduous and will require intense work to succeed."

The Tesla and SpaceX CEO also wrote in the email that there was "no way to sugarcoat the message" about the current economic climate and its impact on Twitter, which depends on advertising.

Twitter did not reply to Insider's request for comment made outside of normal working hours.

Days after Musk finalized his deal with Twitter, employees noticed that the company's "days of rest," implemented by Twitter cofounder Jack Dorsey, had been removed from their calendars, sources told Insider. While Dorsey encouraged staff to avoid burnout, Musk's other companies such as SpaceX and Tesla are known to work long hours.

The change in pace at Twitter is already apparent after a photo was posted on the social-media platform showing a manager sleeping on the floor at its San Francisco headquarters last week.

Bloomberg reported on the letter earlier.

Read the full email that Musk sent to employees:

Sorry that this is my first email to the whole company, but there is no way to sugarcoat the message.

Frankly, the economic picture ahead is dire, especially for a company like ours that is so dependent on advertising in a challenging economic climate. Moreover, 70% of our advertising is brand, rather than specific performance, which makes us doubly vulnerable!

That is why the priority over the past ten days has been to develop and launch Twitter Blue Verified subscriptions (huge props to the team!). Without significant subscription revenue, there is a good chance Twitter will not survive the upcoming economic downturn. We need roughly half of our revenue to be subscription.

Of course, we will still then be significantly reliant on advertising, so I am spending time with our sales & partnerships teams to ensure that Twitter continues to be appealing to advertisers. This is the Spaces discussion that Robin, Yoel and I hosted today:

Links to Twitter Spaces recording called "Elon Q&A: Advertising & the Future.

The road ahead is arduous and will require intense work to succeed. We are also changing Twitter policy such that remote work is no longer allowed, unless you have a specific exception. Managers will send the exceptions lists to me for review an approval.

Starting tomorrow (Thursday), everyone is required to be in the office for a minimum of 40 hours per week. Obviously, if you are physically unable to travel to an office or have a critical personal obligation, then your absence is understandable.

I look forward to working with you to take Twitter to a whole new level. The potential is truly incredible!

Thanks,

Elon