The Elon Musk reign of Twitter has begun in a grueling fashion.

Elon Musk began laying off Twitter employees on Friday, culling the social media service’s 7,500-person workforce a little over a week after completing his blockbuster buyout.

Twitter employees were notified in a companywide email that the layoffs were set to begin, according to a copy of the message seen by The New York Times. Workers were instructed to go home and not go to the offices on Friday as the cuts proceeded. The message, which came from a generic address and was signed “Twitter,” did not detail the total number of layoffs.

“In an effort to place Twitter on a healthy path, we will go through the difficult process of reducing our global workforce,” the email said. “We recognize that this will impact a number of individuals who have made valuable contributions to Twitter, but this action is unfortunately necessary to ensure the company’s success moving forward.”

About half of Twitter’s workers appeared set to lose their jobs, according to previous internal messages and an investor, though the final count may take time to become clear. As the email landed in employee inboxes on Thursday evening, workers posted salute emojis and heart emojis in Slack, the messaging service. Later in the evening, some employees said they had lost access to the company’s systems, a possible prelude to being laid off.

Early Friday morning, the company began to notify some employees that they had been laid off. The emails, some of which were seen by The Times, varied by an employee’s region or country. One New York-based worker received an email saying their job had been “impacted” but that they would remain employed through a separation date in early February.