San Francisco, California - A US regulator is watching events at Twitter with "deep concern" after the social media platform's top privacy and compliance officers reportedly quit.

The Federal Trade Commission (FTC) said new owner Elon Musk was "not above the law," in a statement issued Thursday.

"No CEO (chief executive officer) or company is above the law, and companies must follow our consent decrees," the regulator said. The FTC had "new tools to ensure compliance, and we are prepared to use them," it added.

On Thursday, a number of top security officials resigned from Twitter, according to media reports. Chief information security officer Lea Kissner, chief privacy officer Damien Kieran, and chief compliance officer Marianne Fogarty all reportedly left the company.

The resignations of Twitter's head of trust and safety Yoel Roth and the company's head of client solutions Robin Wheeler followed, media reported.

In May, Twitter agreed to pay a $150 million penalty to settle a privacy lawsuit.

The US government alleged that the social media giant violated FTC regulations for selling users' data, and the company had to agree to new privacy rules.

Meanwhile, Musk reportedly addressed staff on Thursday, warning them that "bankruptcy isn't out of the question," according to multiple reports.

Musk told staff the platform needed "intense work" to turn around its fortunes, media reported.

The tech billionaire had previously warned of a drop in revenue as major brands paused spending on the platform over concerns about content moderation.

He reportedly faces $1 billion in annual interest payments after taking on $13 billion of debt to help fund his takeover of the business.

Musk, who is also the chief executive of Tesla and SpaceX, completed his $44-billion-dollar acquisition of the platform last month.

He immediately cut the workforce and rolled out a new revenue stream with Twitter Blue, which costs $8 a month and includes a "blue check" previously only available to verified users.

Musk has also threatened to crack down on fake and parody accounts, saying that anyone who operates a profile under another person's name and does not mark it as a parody is to be banned without warning.