Google has partnered with one of the nation's largest health care systems to collect millions of Americans' personal health data in an effort to design an artificial intelligence-powered health care service, according to a report.

More than 100 Google employees are already privvy to tens of millions of Americans' lab results, doctor diagnoses, hospitalization records and more. The data will help inform the tech giant's creation of new software that can recommend changes in how patients are cared for, the Wall Street Journal reported Monday.

Neither doctors nor patients were informed of the initiative, dubbed "Project Nightingale," according to the report.

Ascension, the second-largest health care system in the country, said Monday it is working with Google "to optimize the health and wellness of individuals and communities." Its goal is to "deliver a comprehensive portfolio of digital capabilities that enhance the experience of Ascension consumers, patients and clinical providers across the continuum of care," the company said in a statement.

Ascension insists the initiative complies with the Health Insurance Portability and Accountability Act of 1996 and does not violate federal law.