Most of the employees who were fired were engineers, two people familiar with the company's actions said.
People said that the firings came as a surprise. There will be no more layoffs at the company according to Musk.
One of the people said that the employees were laid off for performance reasons and given a month's notice.
Access to work tools and computers were cut off, and a notice of dismissal was sent to employees' personal email accounts, as was the case with previously laid off employees.
Thousands of employees have been laid off, resigned, or fired by Musk. Many employees have had to work on Thanksgiving because of the short-handed team on the micro-blogging site.
The firings are thought to be a result of Musk's new policy requiring engineers and other staff to update him every week about what they worked on, what they hoped to complete, and specific lines of code they wrote. The updates were due on Wednesday because of the holiday.
External engineers have been tapped to work for the company under Musk, and he has even hired a hoaxer who pretended to be laid off from the company. One of the people said that staff believed that Musk had stopped firing suddenly.
A representative for Musk didn't reply immediately.