Ansbach, Germany - A 63-year-old doctor charged with misusing his power to sexually abuse his patients apologized on Monday on the opening day of his trial in Germany's southern state of Bavaria.

"They were my intimate friends and now they have become victims," the physician told the court in Ansbach. He has not been identified under Germany's strict privacy laws.

The prosecution said the doctor exploited the trust of three mentally unstable patients to have sex with them, sometimes without treating the women. One of the women was allegedly raped.

The defendant admitted to having sex with the women but was unable to say how many times.

The doctor's indictment charges his involvement in 122 cases of patient sexual abuse between 2012 and 2015.