JOHANNESBURG, South Africa — Oprah Winfrey flew to South Africa over the weekend for crisis meetings over allegations of sexual misconduct at her exclusive girls’ school south of Johannesburg.

The visit, her second in less than 10 days, followed an admission last week that serious claims of misconduct had been leveled against a matron at the school for underprivileged girls, the Oprah Winfrey Leadership Academy for Girls.

John Samuel, the Chief Executive of the academy, said in a brief statement that the Family Violence, Child Protection and Sexual Offences Unit (FCS) of the South African Police Service had been informed of the internal investigation.

“The inquiry is being conducted in a manner that supports the safe and nurturing environment of the academy, with minimal disruption to campus life. In addition, the academy is providing psychological support and counseling services to our learners,” Samuel said in an official statement, the only comment that the school has made on the affair.

The alleged perpetrator had been removed from the campus and other measures taken to ensure the safety and wellbeing of the pupils, he added.

Rapport, the Afrikaans-language newspaper, reported that the matron is alleged to have grabbed a girl by the throat and thrown her against a wall. The newspaper said that other alleged charges were that the “dorm parent” swore and screamed at the girls, assaulted them and had sexually fondled at least one of them.

The alleged incidents came to light when one of the pupils ran away from the school because the abuse had become intolerable. Her parents informed the school immediately.

Winfrey, who herself was abused as a child, is said to have arrived in South Africa just over a week ago, missing an important Hollywood engagement. She then returned unexpectedly on Friday and left again on Sunday.

She met the school’s executive and private investigators and held a two-hour meeting with the schoolgirls’ parents, who were flown to Johannesburg from all over the country. A report by a private investigator flown in from the United States to conduct an inquiry with a South African counterpart has been handed to the police.

Winfrey issued a terse statement saying she that was taking the incident extremely seriously. “Nothing is more serious or devastating to me than an allegation of misconduct by an adult against any girl at the academy,” she said in her only comment so far on the incident.

The school, at Henley-on-Klip, south of Johannesburg, has been beset by squabbles and sniping since it opened its doors to 150 of the country’s poorest but brightest girls last January.

Local people have complained that they have been excluded from cleaning and kitchen jobs at the school, the local police resent private companies taking care of security and neighbors say that the imposing brick building, which is surrounded by an electric fence, is an eyesore. Parents have complained about over-stringent security interfering with family visits.

Winfrey, who has no children and is known to the girls as “Mama Oprah,” endured an impoverished childhood in America after she was kicked out of her home by her mother at the age of 6. She went on to become the most powerful and richest African-American in U.S. television.

She described the opening of the school, in which she has invested about $45 million of her charitable foundation’s money, as “the proudest, greatest day of my life.”

“I know when you educate a girl, you educate a family, a community — you change the face of a nation,” she said. “This is everything I have ever worked for. Education is the best gift you can ever have as a kid.”

Winfrey, who helped to choose the first entrants from about 5,000 applicants, has built a house in the school grounds and pledged to spend as much time as possible alongside her charges. To qualify the girls had to show academic and leadership potential and come from families with household incomes of less than about $711 a month.

The 28-building campus, built over 52 acres, resembles a luxury retreat rather than a school. It contains state-of-the-art classrooms, computers and science laboratories, a library, a theatre and a wellness center.