An investigation into dozens of possibly induced deaths at two Uruguayan hospitals led to murder charges being filed against two nurses Sunday and a third was charged with covering up a crime, judicial officials said.

Lawyer Ines Massioti, representing one of the nurses, told reporters after a court hearing that the judge ruled the suspects could be held in jail while investigators evaluate physical evidence and testimony.

"We are talking about several deaths," the lawyer said, but declined to give a specific number.

Massioti said her client works at a private hospital and acted "out of pity."

"After 20 years of working in intensive care, with stress and in contact with death, she could not stand it anymore," Massioti said.

No further information was released on the three accused nurses because none had a criminal record.

Earlier in the day, police inspector Jose Luis Roldan said officials suspected some hospital workers brought a sort of poison from Brazil and gave it to patients who were in critical condition at the two hospitals.

Judge Rolando Vomero, who is overseeing the case, told the newspaper El Observador that other hospital staff and relatives of alleged victims reported what could be dozens of cases.

The South American country's Public Health Ministry issued a statement saying it was cooperating with the investigation into "presumed criminal acts linked to the health area." It gave no details about the allegations, but said it was conducting its own investigation and expressed "profound concern."

Roldan said the allegations center on the private Sociedad Espanola hospital and the public Maciel Hospital. Officials at both declined to comment.