STORY: Reuters sources say Twitter has closed its offices and cut staff access until Monday.
It comes as hundreds of employees are leaving the company after the new CEO Elon Musk gave them an ultimatum: Work "hardcore" or get fired.
Some took to the social media app to announce their departure, posting the accompanying hashtag "Love Where You Worked" - past tense.
According to one source, security officers had begun kicking employees out of the office on Thursday evening.
Just a day earlier, Musk emailed Twitter employees asking them to commit to, QUOTE: "working long hours at high intensity".
The email asked staff to click "yes" if they wanted to stick around.
Those that didn't respond would be considered to have quit and given a severance package.
A poll on the workplace app Blind found that more than 40% of 180 poll participants had chosen to leave.
A quarter said they were staying reluctantly and just 7% said they "clicked yes to stay, I'm hardcore."
Blind verifies employees through their work email addresses and allows them to share information anonymously.
Musk has already cut around half of Twitter's 7,500 workforce, including top management.
The departures include many engineers responsible for fixing bugs and preventing service outages, raising questions about the stability of the platform.
The social media company, which has lost many of its communication team members, did not respond to a request for comment.