A day after it was reported that Twitter would lay off 50 percent of staff, Twitter has temporarily shut down its offices to begin layoffs. Some staff told Reuters that hundreds of employees who got this news yesterday immediately logged into Slack to say goodbyes before access was removed. Other workers told Reuters that the content moderation team is expected to be hit hard by layoffs.

One Twitter user whose bio says he formerly served as a Twitter senior community manager tweeted to mark the moment he lost company Slack access. That Twitter staffer assumed that losing Slack access confirmed he was no longer employed but won’t know for sure until today, when employees will find out if they’re fired when they receive an email to their personal inbox. Every employee expected to stick around Twitter will receive an email to their work inbox.

Those email announcements are expected to arrive by noon ET on Friday, according to a Twitter internal email reviewed by Reuters, which informed Twitter staff, "In an effort to place Twitter on a healthy path, we will go through the difficult process of reducing our global workforce on Friday."

Around 3,700 employees are expected to be laid off. This sudden confirmation, however, will at least end the uncertainty for Twitter staff, who were left guessing up until yesterday about whether new Twitter-owner Elon Musk would actually follow through with rumored mass layoffs.

Before layoffs have even been confirmed, though, some staff members are already fighting back. In his rush to cut staff, Musk and his legal team seemingly overlooked or disregarded a federal and California law—the Worker Adjustment and Retraining Notification (WARN) Act—which requires 60 days’ notice to staff in advance of mass layoffs.

Already, Twitter staff is suing Twitter, with five employees filing a class-action lawsuit in a San Francisco federal court on behalf of all Twitter staff. The workers will be represented by attorney Shannon Liss-Riordan, who helped Tesla workers sue after 10 percent of staff was laid off last June. That litigation ended in a win for Tesla that forced Tesla workers out of court and into closed-door arbitration. To prevent another Musk company from doing the same to Twitter staff, Liss-Riordan told Bloomberg that employees have asked the court to stop Twitter from forcing them to sign documents that would waive their rights to take part in the lawsuit.

“We filed this lawsuit tonight in an attempt the make sure that employees are aware that they should not sign away their rights and that they have an avenue for pursuing their rights,” Liss-Riordan told Bloomberg.

Liss-Riordan and Twitter did not immediately respond to Ars’ request for comment.

The class-action lawsuit is asking Twitter to either comply with the WARN Act or provide severance payments, including lost wages, which the employees suing said have not been provided thus far.

Twitter staff is gathering behind the hashtag #OneTeam to provide updates and support through the layoffs. One Twitter user whose bio says he is a “recovering” global head of social and editorial for Twitter posted what he said would be the final tweet sent from his team from the official Twitter account. It’s a screencap that just says, “bye literally everyone.”