Personal information for more than 4,300 people may have been compromised in a data breach within the Minnesota Department of Human Services, the agency said Friday.

The breach came as a result of an email phishing attempt on July 2. The next day, an employee's email account was "secured" after officials learned of the incident, the department said.

It said the hacker may have accessed full names, dates of birth, contact information, treatment information, medical diagnoses, demographic data and Social Security numbers for 4,329 people.

"We have no evidence that this information was actually downloaded or misused," the department said.

The department has sent letters to individuals whose information was potentially accessed.