Twitter has notified employees that the company’s office buildings will be temporarily closed, effective immediately.
In a message seen by the BBC, workers were told that offices would reopen on Monday 21 November.
He did not give a reason for the move.
The announcement comes amid reports that a large number of staff have quit after new owner Elon Musk told them to sign up for “long hours at high intensity” or leave.
The message went on to say: “Continue to comply with company policy by refraining from discussing confidential company information on social media, with the press or elsewhere.”
Twitter did not immediately respond to a request for comment from the BBC.
This week Musk told Twitter staff they had to commit to working “long hours at high intensity” or leave the company, according to reports.
In an email to staff, the company’s new owner said workers would have to agree to the pledge if they wanted to stay, the Washington Post reported.
Those who don’t sign up by Thursday will receive three months’ severance pay, Musk said.
Earlier this month the company said it was cutting about 50% of its workforce.
Today’s announcement that Twitter has temporarily closed its offices came amid indications that a large number of employees have now also quit as they have not accepted Mr Musk’s new terms.
Employees have tweeted using the hashtag #LoveWhereYouWorked and a greeting emoji to show they are leaving the company.
A former Twitter employee who spoke on condition of anonymity told the BBC: “I think when the dust clears today, there will probably be less than 2,000 people left.”
They added that everyone in their team had been fired.
“The manager of that team, his manager got fired. And then that manager’s manager got fired. The person above was one of the executives fired on the first day. So there’s nobody left in that chain of command.”
Before Musk took control of Twitter, the company had about 8,000 employees. The company was also reported to employ thousands of contract workers, the majority of whom are believed to have been laid off.
Another person said they had resigned even though they were prepared to take on the increased workload Mr. Musk demanded.
“I didn’t want to work for someone who threatened us via email multiple times that only ‘super tweeps should work here’ when I was already working 60-70 hours a week,” they said.
The world’s richest man became chief executive of Twitter after buying the company last month in a $44bn (£37bn) deal.
After sending the message about closing Twitter’s offices, and in an apparent reference to the problems he has faced since buying the company, Mr Musk tweeted:
“How do you make a small fortune in social media? Start with a big one.”