A Twitter employee raised concerns over the company's FTC compliance under new owner Elon Musk, an internal letter shared Thursday showed.

Since taking over the social media site, Tesla CEO Musk has initiated a number of changes, including firing nearly half of its staff before asking some to return, introducing changes to the verification process, including the coveted check-mark as a Twitter Blue perk, and telling staff to cut costs. The company has seen both users and advertisers leave the site in recent weeks. Musk on Thursday also ended the company's remote work policies.

The chaos has left employees scrambling, particularly over data and testing practices. The turmoil has also seen three key employees leave their posts.

Damien Kieran, Twitter's chief privacy officer, as well as chief information security officer Lea Kissner and Marianne Fogarty, chief compliance officer, all resigned Thursday, The Verge reported.

Kissner confirmed their decision to step down in a tweet Thursday.

"I've made the hard decision to leave Twitter. I've had the opportunity to work with amazing people and I'm so proud of the privacy, security, and IT teams and the work we've done," read the tweet.

After previously quoting a $20 fee for Twitter Blue, Elon Musk suggested a lowered amount of $8 in a Nov. 1 exchange with author Stephen King.

Musk earlier this week, suggested putting all of Twitter behind a paywall by suppressing tweets from non-Twitter Blue accounts, pricing out much of the site's user base.

"Elon has shown that his only priority with Twitter users is how to monetize them. I do not believe he cares about the human rights activists. the dissidents, our users in un-monetizable regions, and all the other users who have made Twitter the global town square you have all spent so long building, and we all love," a lawyer on the company's privacy team wrote in note to staff that was obtained by The Verge.

Musk's Twitter takeover was finalized on Oct. 27 after he had previously entered a binding agreement to purchase the platform for $44 billion.

In May, the company reached a $150 million settlement with the FTC over privacy concerns.

The Thursday letter warns that Musk's handling of Twitter, along with pressures on employees, could lead the company to breach its FTC agreements. With a possibility of massive fines to follow, the event could also threaten Twitter's future, the letter said.