"I left the stage because I was not well,” he said. “I am an artist. I am very sensitive.” He blamed La Scala for not halting the performance to give him a chance to recover, as normally happens when a singer is taken ill.

He denied that [La Scala's director] spoke to him for 30 minutes. “He told me just that, ‘Return, or it will be very bad for you,’ ” Mr. Alagna said.

Then, he changed tack and said his salute [he did a military salute to the audience before leaving the stage] reflected recognition that the public had spoken. “So be it. I respect your decision,” he said. “If people don’t like me, why do I have to force them to listen to me?” And yet, he continued, the real disrespect to the audience came from [the director] by canceling his [future] performances. “Those people paid to see me, to hear me,” he said.

He also hinted at darker forces arrayed against him, saying that the cover, Mr. Palombi, was already warming up in his dressing room before the performance, and that three mysterious figures made karate chop motions at him outside the stage door beforehand.

“There’s something very strange,” he said, adding that he may have been the inadvertent target of audience members who resent [the director of La Scala's] French nationality.