Elon Musk said Sunday that a "cage match" he and Meta CEO Mark Zuckerberg have seemingly agreed to as a fund-raiser will be carried live on X, formerly known as Twitter, which he owns.

"Zuck v Musk fight will be live-streamed on X," Musk posted. "All proceeds will go to charity for veterans."

Zuckerberg soon hit back on Threads, the new app he launched last month in a direct challenge to what was then still called Twitter, saying he was ready.

"Shouldn't we use a more reliable platform that can actually raise money for charity?" he added, in a dig at the wave of problems faced by Musk's platform since he took over last year.

The two billionaire entrepreneurs, who in the past have occasionally jousted from afar, became direct competitors after Zuckerberg's Meta launched its Twitter-like Threads platform in early July, quickly drawing 120 million users, according to Quiver Quantitative.

Musk then posted on X, "I'm up for a cage match if he is lol," referring to a form of Mixed Martial Arts in which rival fighters employ a variety of techniques -- like wrestling or Brazilian jiu-jitsu -- while limited by few rules.

Zuckerberg, a martial arts enthusiast who has taken part in jiu-jitsu competitions, responded to Musk's initial, seemingly humorous, challenge by replying on Instagram "Send me location."

The exchange sparked a torrent of reactions on social media, as well as prompting a lively round of betting on the potential winner.

The 39-year-old Zuckerberg, with his fighting experience, emerged as the clear favorite despite the decided size advantage of Musk, who is 52.

No date has been set for the fight, which -- if it does happen -- is expected to take place in Las Vegas.

The two tech giants have clashed over the years on issues ranging from politics to artificial intelligence.

But the arrival of Threads heightened the pressure on the already troubled Twitter, which Musk rebranded to X last month.

Musk bought that social network for $44 billion before announcing massive layoffs and opening the platform up to conspiracy-minded posters, leading several advertisers to turn elsewhere.