Robert O’Neill, the former Navy SEAL who claims to have killed Osama bin Laden, said Thursday that he had been banned from flying with Delta Air Lines because he removed his face mask on a flight.

On Wednesday, O’Neill tweeted a maskless selfie that appeared to show him aboard a Delta plane and that has since been deleted (though not before being archived by multiple news outlets). The following day, he wrote that he had been banned “for posting a picture” and later commented, “Thank God it wasn’t @Delta flying us in when we killed bin Laden … we weren’t wearing masks …”

“Part of every customer’s commitment prior to traveling on Delta is the requirement to acknowledge our updated travel policies, which includes wearing a mask,” the airline said in a statement to The Washington Post. “Failure to comply with our mask-wearing mandate can result in losing the ability to fly Delta in the future.”

Delta is one of several U.S. carriers that say they will deny service to customers who refuse to wear masks. The company’s CEO said last month that at least 100 people had been barred from flights because of their unwillingness to cooperate. The airline allows passengers to take off masks while eating or drinking only, and requires those claiming a medical exemption to undergo an extensive screening process that can take up to an hour and includes a telehealth consultation with a medical professional.

Since identifying himself as bin Laden’s shooter, O’Neill has become a celebrity in some conservative circles. But he has also faced criticism for revealing detailed information about the raid, and accused of breaking a tradition of secrecy to gain publicity. Other members of his former SEAL team have also suggested that bin Laden was already dead before O’Neill shot him.

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