Elon Musk has given Twitter staff an ultimatum to sign an agreement by Thursday evening that they will work with “hardcore” intensity or otherwise leave the company.
Mr Musk, the Twitter chief executive, asked employees in an email if they wanted to stay with Twitter, and that “only exceptional performance will constitute a passing grade”, Bloomberg and The Washington Post reported.
For Twitter to succeed, “we will need to be extremely hardcore,” Mr Musk said in the email.
Twitter will be more dominated by engineers going forward, and the social media platform is a “software and servers company” at its heart, Mr Musk reportedly said in the email.
Design and product management functions will “still be very important and report to me”, he said.
The message added that anyone who did not sign up would receive three months' severance pay.
Twitter has been going through a tumultuous period since Mr Musk's acquisition of the social media platform at the end of last month for $44 billion.
Thousands of staff were fired, as he said the company was losing $4 million per day.
Earlier this week, Mr Musk said that he had “too much on his plate”, as he also dealt with running Tesla and SpaceX.
“I'm not sure how many people would actually like to be me,” he said. “They would like to be what they imagine being me, which is not the same thing as actually being me. The amount that I torture myself is next level, frankly.”
He said during a Tesla pay package trial in a Delaware court on Wednesday that he expected to reduce his time at Twitter, as “there's an initial burst of activity needed post-acquisition to reorganise the company”.
He then tweeted that he would continue to run Twitter “until it is in a strong place, which will take some time”.
Twitter co-founder and former chief executive Jack Dorsey said he would not accept a return to the company as chief executive.
When asked on Twitter if he would take on the position, he simply replied “nope”.
Mr Musk said during the trial in Delaware that most of his time for the past few weeks had been spent at Twitter, though he said the “fundamental organisational restructuring” would be completed by the end of next week.
Earlier this week, The New York Times reported that he was firing staff who were openly criticising him.
Mr Musk’s team ordered nearly two dozen employees who spoke out publicly and privately against him to be fired, the newspaper said.
They were told that their contracts had been terminated for “violating company policy”, the Times said.
Meanwhile, his mother, Maye Musk, reportedly said in a BBC documentary about her son that people should “stop being mean to him” and added that he “gets a lot of hate”.