SAN FRANCISCO, United States – Twitter owner Elon Musk on Monday opened fire against Apple over its tight control of what is allowed on the App Store, saying the iPhone maker has threatened to oust his recently acquired social media platform.

Musk also joined the chorus crying foul over a 30 percent fee Apple collects on transactions via its App Store -- the sole gateway for digital content to get onto its coveted mobile devices.

A series of tweets fired off by Musk included a meme of a car with his first name on it veering onto a highway off-ramp labeled "Go to War," instead of continuing onwards towards "Pay 30%."

The billionaire CEO also tweeted that Apple has "threatened to withhold Twitter from its App Store, but won’t tell us why."

Apple did not immediately reply to a request for comment.

To be allowed on the Apple and Google app stores, social networking services must have effective systems for moderating harmful or abusive content.

But since taking over Twitter last month, Musk has cut around half of Twitter's workforce, including many employees tasked with fighting disinformation, while an unknown number of others have voluntarily quit.

He has also reinstated previously banned accounts, including that of former president Donald Trump.

Yoel Roth, the former head of trust and safety at Twitter who left after Musk took over, wrote in a New York Times op-ed that "failure to adhere to Apple’s and Google’s guidelines would be catastrophic," and risk "expulsion from their app stores."

Describing himself as a "free speech absolutist," Musk believes that Twitter should allow any posts permitted by law, and on Monday described his actions as a "revolution against online censorship in America."

Though Musk says Twitter is seeing record high engagement with him at the helm, his approach has startled the company's major moneymaker -- advertisers.

In recent weeks, half of Twitter's 100 top advertisers have announced they are suspending or have otherwise "seemingly stopped advertising on Twitter," an analysis conducted by nonprofit watchdog group Media Matters found.

Musk on Monday accused Apple of also having "mostly stopped advertising on Twitter."

"Do they hate free speech in America?" he asked, before replying with a tweet tagging Apple CEO Tim Cook.

Sarah Roberts, an information studies expert at University of California, Los Angeles, told AFP that "Musk didn’t understand that Twitter itself was a brand, had cachet."

"Now companies don’t even want to be associated with it. It’s not even that they worry about the content. Twitter is a tainted brand, a brand non grata companies don’t want to be associated with," she added.

Musk on Monday also called Apple's fee on transactions through its App Store a "secret 30% tax."

He shared a video released last year by Fortnite maker Epic Games that portrayed Apple as an oppressor in a mocking spin on a famous "1984" ad for Macintosh computers.

Apple has clashed in court with Epic, which has sought to break Apple's grip on the App Store, accusing the iPhone maker of operating a monopoly in its shop for digital goods or services.

A federal judge last year ordered Apple to loosen control of its App Store payment options, but said Epic had failed to prove that antitrust violations had taken place.