The Swedish Academy, which hands out the coveted Nobel Prize for Literature, said an investigation has found that "unacceptable behaviour in the form of unwanted intimacy" took place within its ranks.
The 18-member board has in recent weeks been embroiled in a sex abuse scandal that the investigation report concluded today was "not generally known".
It has led to the departure of six members of the Academy and tarnished the prize's reputation.
Sweden's prime minister, the king and the Nobel board have all expressed their concerns.
The academy commissioned lawyers to investigate sexual misconduct claims from 18 women against Jean-Claude Arnault, a major cultural figure in Sweden who is married to Katarina Frostenson, a poet who is a member of the academy.