Elon Musk has apologized for calling a British diver involved in the Thailand cave rescue a pedophile.

In a series of tweets late today, the Tesla CEO said he had “spoken in anger” on Sunday after diver Vern Unsworth accused Musk and SpaceX engineers of orchestrating a “PR stunt” by sending a small submarine to help divers rescue the 12 Thai soccer players and their coach from a flooded cave.

Musk says Unsworth’s criticism upset him but he should not have branded the diver a “pedo.” Musk said, “The fault is mine and mine alone.”

Musk’s Sunday tweet, later deleted, had sent investors away from Tesla stock, which fell nearly 3 percent Monday. Unsworth told CNN earlier this week that he is considering legal action.