Twitter reportedly notified employees that it would temporarily close its offices and cut badge access until Monday.
The move comes after numerous employees chose to leave the company following an ultimatum issued by new CEO Elon Musk, telling workers that they would have to choose to work "long hours at high intensity" or leave. Hundreds of employees were estimated to have quit, but Musk assured on his Twitter account that the "best people are staying."
The resignations included many engineers who are responsible for preventing service outages and fixing bugs, and a source told Reuters that the version of the app used by employees began to slow on Thursday night. Since taking over, Musk has eliminated roughly half the company's workforce.
In his memo to staff, Musk wrote that employees will need to be "extremely hardcore" and the remaining staff at Twitter were asked to decide by Thursday evening if they wanted to remain a part of the business.
Reuters reported, citing a source, that security officers started kicking some employees out of one office on Thursday night.
Musk has since backpedaled from his previous stance, saying that he would allow some employees to stay remote with manager approval. Workers would also be expected to have "in-person meetings with your colleagues on a reasonable cadence, ideally weekly, but not less than once per month."
A new lawsuit from a former Twitter engineering manager filed in San Francisco federal court on Wednesday said that Musk's mandate that employees stop working remotely and put in "long hours at high intensity" violates the federal Americans with Disabilities Act.
Twitter is already facing a proposed class action lawsuit, claiming it violated federal law by laying off about half the company's workforce earlier this month.
Meanwhile, a video went viral of Twitter's San Francisco headquarters with a banner jabbing at Musk.
FOX Business' request for comment from Twitter was not immediately returned.
FOX Business' Aislinn Murphy, Reuters and The Associated Press contributed to this report.