Oprah in tearful apology to parents of abused children in African school

Oprah Winfrey, the US talk-show queen, has asked parents for forgiveness following allegations of abuse at her exclusive girls' school in South Africa.

At an emotional meeting at her Leadership Academy for Girls near Johannesburg, Ms Winfrey said she would do everything in her power to ensure a prosecution, telling the packed marquee: "I've disappointed you. I'm so sorry. I'm so sorry."

Ms Winfrey has visited the school for underprivileged girls she bankrolls at Henley on Klip at least twice in the past few weeks, after accusations that one of the "dorm parents", or matrons, had abused pupils.

Reports said the matron apparently grabbed a girl by the throat and threw her against a wall. The unnamed woman is also accused of swearing and shouting at the girls and sexually fondling at least one pupil. The allegations surfaced when a student ran away from the school claiming the situation had become intolerable.

Ms Winfrey once claimed that the academy would become a "model school for the rest of the world", but is now seeing her dream unravel. At the meeting she said she had given the alleged victims her email address, personal phone number and postal address so they could contact her at any time. Apart from the dorm parent, Ms Winfrey has sent at least two other staff members, including the principal, named only as Dr Mzimane, on leave following the accusations. The alleged victims have accused Dr Mzimane of failing to act after students complained of abuse. Police and special US investigators are now looking into the matter.

Ms Winfrey, reportedly in tears, told the meeting: "I trusted her [Dr Mzimane]. When I appointed her, I thought she was passionate about the children of Africa. But I've been disappointed." A father of one of the pupils responded by telling her: "It's not your fault. We don't blame you. You trusted them. You have more passion for the school... than anyone else in this country."

Ms Winfrey, who is reportedly worth $2.1bn (£1.02bn), spent $40m building the centre, and helped interview many of the 3,500 girls who applied for the first 150 places. The school hopes to cater for 450 pupils by 2011.

The idea for the academy came when Ms Winfrey staged a series of Christmas shows for poor children in South Africa in 2004, after which Nelson Mandela requested she get involved in educational programmes. The result is a 28-building campus on 52 acres, a 10,000-book library, gym, sports fields and a theatre.

Despite its aims, the academy was not universally welcomed by locals, who complained about the size of the buildings and the electric perimeter fence. They also claimed to have been excluded from kitchen and cleaning jobs.

When the abuse accusations first surfaced Ms Winfrey said: "Nothing is more serious... than an allegation of misconduct by an adult against any girl at the academy. I will do everything... to ensure their safety."