Tesla CEO Elon Musk apologized on Tuesday for calling one of the cavers crucial to the rescue of a Thai boys' soccer team a "pedo," accepting that the tweet to his 22.3 million followers was unjustified. Musk backed into the apology, taking full responsibility for his maligning of British cave expert Vernon Unsworth after noting that he leveled the baseless public allegation of pedophilia in "anger after Mr. Unsworth said several untruths & suggested I engage in a sexual act with the mini-sub."

Unsworth, who's extensive knowledge of the layout of the Tham Luang cave in northern Thailand proved crucial to the operation which saved 12 young soccer players and their assistant coach, accused Musk and SpaceX engineers of orchestrating a "PR stunt" by sending a small submarine to help the rescue divers.

"I apologize to Mr. Unsworth and to the companies I represent as leader. The fault is mine and mine alone," Musk said about his tweets, in which he first called Unsworth a "pedo" and then doubled down on the claim, tweeting from his official account: "Bet ya a signed dollar it's true."

Nonetheless, his actions against me do not justify my actions against him, and for that I apologize to Mr. Unsworth and to the companies I represent as leader. The fault is mine and mine alone. — Elon Musk (@elonmusk) July 18, 2018

Musk's Sunday tweet, which he later deleted, had sent investors away from Tesla stock, which fell nearly 3 percent Monday.

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Asked on Monday if he would take legal action against Musk over the allegation, Unsworth said: "If it's what I think it is yes."

The caver told French news agency AFP that he would make a decision when he returned to the U.K. this week, but said the episode with Musk "ain't finished."

"He's just a PR stunt merchant -- that's all he is," Unsworth added.

Unsworth, who lives part of the year in Thailand, took part in the gargantuan 18-day effort to retrieve the 12 boys and their coach, a mission that ended on July 10 when the last five members were extracted.

Musk initially provoked condemnation after tweeting that the Thai rescue chief, who had declined the entrepreneur's offer of a mini-submarine prototype to help in the international effort, was not really in charge of the operation.