NEW YORK, July 18 (Xinhua) -- U.S. tech billionaire Elon Musk has apologized to a British caver involved in the Thai rescue mission for calling the latter a "pedo."

Musk said on Twitter Wednesday that "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."

Musk made the "pedo" claim in two now-deleted tweets after Vernon Unsworth, a caver based in Thailand who participated in the Tham Luang cave rescue of 12 teen footballers and their coach, dismissed his miniature submarine as a "PR stunt." The kid-size submarine was intended for the rescue operation but ended up being of no help.

Unsworth said later he was considering legal action against the tech magnate who is CEO of several U.S. companies including Tesla and SpaceX over the unfounded and disparaging claim.

Musk's retaliatory words drew concerns from analysts and investors, amid Tesla's struggle to be a mass-market automaker.

Gene Munster, a famed analyst and the managing partner at Loup Ventures, wrote an open letter to Musk urging him to step back from Twitter outbursts so as to "regain investor confidence."