Elon Musk has sent his first email to Twitter’s staff, warning employees to prepare for “difficult times ahead” and putting an immediate end to remote work.

In the email reported by Bloomberg News, Musk warned that a weaker economic environment in the US would mean difficulties for Twitter. Analysts have been projecting slower growth in advertising spend in 2023, and, as a business where ads account for roughly 90 percent of revenue, Twitter will be strongly affected by this.

Musk said there was “no way to sugarcoat the message” about these challenges. He also reportedly told employees that they were expected to be in the office for a minimum of 40 hours a week and that he would only approve remote work on a case-by-case basis. Musk has previously signaled his opposition to remote work, but said in June in a Q&A with Twitter employees that “exceptional” workers would be allowed to continue the practice.

“The road ahead is arduous and will require intense work to succeed,” wrote Musk in the email seen by Bloomberg. He added in another message that “over the next few days, the absolute top priority is finding and suspending any verified bots/trolls/spam.”

Twitter’s advertising revenue will also be affected by Musk’s chaotic management of the site. A number of major companies, including insurer Allianz and automaker Audi, have paused ad spend on Twitter in response to Musk’s takeover and his ambitions to scale back moderation on the site.

In a public Q&A on Wednesday, Musk told advertisers that he had heard their concerns and that their have yet to be any changes to the platform’s content moderation policies. Musk has previously blamed “activist groups” for pressuring advertisers to drop campaigns (without offering any evidence for this claim) and accused these same unnamed groups of “trying to destroy free speech in America.”

Meanwhile, Twitter’s most visible change to its verification system — allowing anyone to pay $8 for a badge that previously denoted an official account — has allowed countless users to masquerade as brands and celebrities. Musk reportedly said in his emails to staff that he eventually wants the Twitter Blue subscription service to account for half of the company’s revenue.