PORTLAND — Portland’s police chief has appealed to Hillary Rodham Clinton to help change federal housing laws he says have created a “climate of fear” in low-income housing projects.

In a letter to the first lady, Chief Michael J. Chitwood asked that the Clinton administration’s health care reform plan include provisions to keep the elderly and the mentally ill from being forced to live in the same housing developments.

Chitwood had expressed concern in the past about law enforcement problems arising from the growing number of mentally ill moving into housing projects traditionally reserved for senior citizens.

The chief said he was reminded of the problem last week when he helped the Secret Service select an elderly-housing development for Clinton to visit during her swing through Maine on Monday to promote the health plan.

His first choice, Harbor Terrace, was rejected as a security risk because of the high number of police calls there last year. The first lady visited the 100 State St. complex instead.

In his letter to Clinton, which he gave to Sen. George J. Mitchell to deliver, Chitwood said the housing complexes have turned into “combat zones” and the elderly live in a “climate of fear.”

“Why are we asking our elderly citizens to bear the burden of our mentally ill?” Chitwood wrote. “Must their quality of life be diminished due to the woefully inadequate health care system in this country?”

The mentally ill are eligible by law to live in subsidized housing projects that once were occupied almost exclusively by the elderly. As a result, growing numbers of nonelderly have claimed spots in such developments in Maine and elsewhere.

Many older tenants claim the younger occupants party loud and late, disrupt their buildings, intimidate the elderly, and send fear through the projects.

People with mental illnesses claim they are shunned by the elderly and labeled as troublemakers for no good reason. But, they say, they need subsidized housing, too.

Housing managers and advocates for the mentally ill agree that mixing the groups can cause problems.