The billionaire said in a follow-up email, "I would appreciate it if you could fly to SF to be present in person," adding that he would be at Twitter's San Francisco headquarters until midnight and would return Saturday morning.

Musk ordered employees to email him a summary of what their software code has "achieved" in the past six months, "along with up to 10 screenshots of the most salient lines of code."

"There will be short, technical interviews that allow me to better understand the Twitter tech stack," Musk wrote in the earlier memo.

He said he would try to speak with remote employees by video. Musk also said that only people who cannot physically get to the company's headquarters or have a family emergency would be excused.

Hundreds of Twitter employees were estimated to have decided to quit the beleaguered social media company following a Thursday deadline from Musk that staffers sign up for "long hours at high intensity," or leave.

In his first email to Twitter employees this month, Musk said, "We are also changing Twitter policy such that remote work is no longer allowed, unless you have a specific exception."

He added, "Managers will send the exceptions lists to me for review an approval."