One image shows a room with a double bed, including a wardrobe and slippers.

An ex-worker said new Twitter boss Elon Musk has been staying at the headquarters since he bought the firm.

He last month emailed all Twitter staff saying they "will need to be extremely hardcore" to succeed.

San Francisco's department of building inspection has confirmed it is investigating potential violations following a complaint.

In response, Musk said the city was attacking companies for providing beds to "tired employees".

In a now-deleted tweet, Musk posted that he would work and sleep in the office "until the org is fixed".

Twitter did not immediately respond to a request for comment.

Last month, Musk emailed all staff at the company, saying they would need to work "long hours at high intensity".

"Only exceptional performance will constitute a passing grade," he wrote. 

"He's now making them [workers] sleep at Twitter," California state senator Scott Wiener said on Wednesday. "It's clear that he doesn't really care about people. He doesn't care about the people who work for him."

"A department of building inspection official said, "We need to make sure the building is being used as intended".

In a reply to a journalist on Twitter, Musk posted that the city should prioritise protecting children from the consequences of opioid drug misuse.

The bedrooms are reportedly also used to accommodate staff from Tesla and other Musk-owned businesses brought in to work at Twitter, "some of whom travel to Twitter for work meetings," according to sources.

In May 2020, before Musk's takeover, Twitter told employees they could work from home "forever" if they so wished because its remote-working measures during Covid lockdowns had been a success.

Last month, Musk said remote working would end.

BBC