Twitter Chief Executive Officer Elon Musk said in an email to employees that, effective immediately, remote work would no longer be allowed and that they would be expected to be in the office for at least 40 hours per week, Bloomberg News reported Thursday.

Musk also told employees in his first email missive that he wants to see subscriptions account for half of Twitter's revenue.

Musk called on the Twitter staff to buck up, saying, "The road ahead is arduous and will require intense work to succeed." He said a weaker economic environment in the United States will impact Twitter's advertising revenue and margins, The Verge reports.

There is "no way to sugarcoat the message" about these challenges, Musk added.

"Over the next few days, the absolute top priority is finding and suspending any verified bots/trolls/spam," Musk said.

In a Q&A Wednesday, Musk told advertisers that any changes to Twitter's content moderation policies have yet to be decided.

Shortly after taking control of Twitter, Musk slashed some 3,700 employees, roughly half of the social media platform's staff.