Fr Dartmann said he was ashamed the order did not investigate
The head of a Catholic order in Germany has apologised for the systematic sex abuse apparently committed by two priests at a prestigious Berlin school.
Fr Stefan Dartmann said students at the Jesuit-run Canisius College had complained in 1981, much earlier than the order had previously admitted.
The Jesuit said he was ashamed that the college and the order had left the complaint unanswered.
The number of victims was greater than originally believed, he added.
"I apologise that those responsible at the time did not investigate and react as they should have done," said Fr Dartmann.
He said he was aware of 25 cases not just in Berlin, but at two other Catholic schools in Hamburg and in the Black Forest, where the priests had been transferred.
Most of the victims had been boys aged around 13 or 14, but young girls were also targeted for abuse.
Fr Klaus Mertes, the Canisius College's director, said last week two former teachers had repeatedly and systematically abused students in the 1970s and 80s.
The prosecutor's office is investigating the cases but experts say they can no longer be prosecuted because of Germany's statute of limitations.
The college is the alma mater of many politicians and business leaders
Both men, named in the German press as Peter R and Wolfgang S, left the Jesuit order in the 1980s.
However, there is suspicion they may have continued to abuse children at institutions in Spain, Mexico and Chile, says the BBC's Oana Lungescu in Berlin.
Last month, Wolfgang S, who lives in Chile, sent a letter of apology to some of his victims.
According to press reports, a former student tried to stab Peter R in the 1980s before taking his own life.
Founded as an all-boys school and the alma mater of many German politicians and business leaders, Canisius College turned co-educational in the late 1970s.