(CNN) -- An HIV-positive German pop singer went on trial on Monday accused of failing to tell sexual partners about her condition, causing one of them to become infected.

Nadja Benaissa, 28, former singer in the girl band No Angels, is charged with causing grevious bodily harm and attempted bodily harm, a court spokesman told CNN.

Benaissa had unprotected sex on five occasions between 2000 and 2004 with three people and did not tell them she was infected, Agence France-Presse reported the charge sheet as saying. She had allegedly known her status since 1999.

Benaissa admitted not telling sexual partners she was HIV-positive but denied intending to infect anyone, according to AFP. "I am sorry from the heart," she told the court, according to media reports.

One of the three men Benaissa allegedly slept with has since been confirmed as having HIV, prosecutors told an earlier hearing, AFP reported.

German newspaper Bild reported that Benaissa's attorney read a statement in which she said she believed there was little chance of her passing on the virus and did not want it made public because of the harm it might cause her daughter and the band.

Bild also reported that one of Benaissa's alleged victims told the court he had unprotected sex with Benaissa on about three occasions. He said he went to the doctor after learning of Benaissa's condition from her aunt, and discovered he had contracted the virus.

He told Benaissa: "You have borne so much suffering in the world," according to the newspaper.

No Angels became Germany's most successful all-female group after being formed on the international television show "Popstars" in 2000.

The band reformed in 2007 and competed in the 2008 Eurovision Song Contest.

Benaissa is appearing in youth court because she was 17 at the time of the first alleged offence.

The fact that Benaissa was HIV-positive was not made public until her arrest in April last year, AFP reported. She spent 10 days in custody after her arrest before being released on bail.

The trial is expected to last five days and hear from witnesses including fellow members of No Angels.