Sacramento: Los Angeles police said on Tuesday that they had launched a criminal investigation into accusations that a gynaecologist at the University of Southern California engaged in sexually inappropriate conduct with students over a 26-year period.

Officials said the investigation would have international scope as they seek input from up to 10,000 women who were treated by Dr George Tyndall at USC's student health clinic.

The scandal has prompted more than a dozen lawsuits and forced the resignation of the institution's president.

Police so far have the names of 52 women who have said that Tyndall, 71, touched them, spoke to them inappropriately or engaged in other misconduct while examining them as a USC doctor from 1990 to 2016, Deputy Chief Justin Eisenberg said at a news conference in Los Angeles.

Police will work closely with the Medical Board of California, which licenses doctors, and will ultimately refer any evidence of criminal wrongdoing to prosecutors, Eisenberg said.