Plácido Domingo, who is facing multiple allegations of sexual harassment, has apologised for “the hurt” caused to his accusers, saying he accepted “full responsibility” for his actions.

In a statement, the singer, director and conductor said: “I have taken time over the last several months to reflect on the allegations that various colleagues of mine have made against me. I respect that these women finally felt comfortable enough to speak out, and I want them to know that I am truly sorry for the hurt that I caused them. I accept full responsibility for my actions, and I have grown from this experience.”

The 79-year-old – a director, conductor and star soloist at some of the world’s most prestigious opera houses – has been accused by multiple women of forcibly kissing, grabbing or fondling them in incidents dating to the 1980s.

Domingo has previously denied the allegations, saying his interactions and relationships were “always welcomed and consensual”.

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His statement comes after an investigation by the American Guild of Musical Artists (AGMA), the union representing US opera performers, concluded that Domingo had, in fact, engaged in ​inappropriate activity “ranging from flirtation to sexual advances, in and outside of the workplace,” and that “many of the witnesses expressed fear of retaliation in the industry as their reason for not coming forward sooner.”

The union’s investigation was the first of two inquiries launched after last year multiple women accused Domingo of sexual harassment and abusing his power when he held senior management positions at Washington National Opera and Los Angeles Opera. The second, still ongoing, is by LA Opera, where Domingo was general director from 2003 until he resigned in October. LA Opera has not said if it will make its findings public.

Associated Press reports that the AGMA investigation found that the allegations included unsolicited physical touching that ranged from kisses on the mouth to groping, late-night phone calls in which Domingo asked women to come to his residence and inviting women to go out with him socially with such persistence that some said they felt as if they were being stalked.

Two women told AGMA lawyers they had sexual relations with Domingo and felt compelled to participate because of his position of authority and potential to damage their careers, according to the people familiar with the investigation.

The guild found the witness accounts to be credible based on the number of people who came forward, the similarities of their stories, corroborations of their accounts, and the common theme that Domingo’s behaviour and reputation were such widespread knowledge that women at his companies were warned to avoid being in close contact with him.

Domingo said: “I understand now that some women may have feared expressing themselves honestly because of a concern that their careers would be adversely affected if they did so. While that was never my intention, no one should ever be made to feel that way. I am committed to affecting positive change in the opera industry so that no one else has to have that same experience. It is my fervent wish that the result will be a safer place to work for all in the opera industry, and I hope that my example moving forward will encourage others to follow.”

A number of US opera companies have cancelled planned appearances by Domingo and he withdrew from others under pressure. But no European performances have been affected, with the singer performing in Austria, Hungary and Russia since the allegations first surfaced. A Covent Garden appearance this summer is still scheduled.