PORTLAND (AP) — Mercy Health System of Maine has entered into a letter of intent to sell Mercy Hospital and its other facilities to a Boston-based hospital chain under a plan in which the hospital would keep its Catholic affiliation, Mercy officials announced Monday.

The nonbinding letter of intent is the first step toward reaching a final sales agreement with Steward Health Care System LLC, Mercy Health System said.

The nonprofit Mercy Health System of Maine includes the two Mercy Hospital campuses in Portland, its affiliated care facilities and VNA Home Health Hospice. The for-profit Steward Health Care System has 10 community hospitals in Massachusetts, six of which are Catholic.

Terms of the potential deal were not disclosed.

Steward intends to retain Mercy’s current management team and employees, and service to patients will be unaffected by the transition, said Eileen Skinner, Mercy president and CEO.

Catholic Health East, which helped support Mercy, supports the alignment of Mercy and Steward.

“We feel that Steward is the best fit to help Mercy achieve its mission goals, preserve its Catholic legacy, and continue to provide quality, cost-effective care for residents of the greater Portland area,” said Judy Persichilli, CHE’s president and chief executive officer.

Over the past two years, Steward has committed nearly $600 million in capital investments to its hospitals in Massachusetts, and the company would make a significant investment in Mercy facilities and programs, including VNA Home Heath Hospice, officials said.