ALBUQUERQUE, N.M. (AP) — No laws were broken and no regulations were violated by one of the largest U.S. public housing authorities despite criticism over management and its spending of millions of dollars in federal grants to address a persistent and growing need for homes on the Navajo Nation, according to a final report by the U.S. Department of Housing and Urban Development.

Regional investigators with the federal agency visited housing projects on the Native American Indian reservation in New Mexico and Arizona earlier this year, conducted interviews and reviewed housing plans and contracts the Navajo Housing Authority had with developers before issuing their findings last week. The report was made public Monday.

Investigators identified one concern about an Arizona project in which the housing authority did not retain legal control of the site through its 2001 agreement with the developer. That led to problems and the homes remaining vacant for years, the report said.

Investigators reported that the restructuring of the Navajo Housing Authority and other reforms in recent years have resulted in improved oversight and less risk that federal funds will be misspent.

New board members who oversee the housing authority said the federal investigation helped to clarify misinformation about several projects that the authority undertook between 2001 and 2010.

"We have done our best to fix the problems of the past. However, we are the largest, rural housing agency in the U.S. and we know we will continue to have challenges, but we are committed to finding ways to overcome the challenges," the board members said in a statement Tuesday.

An investigative series published by The Arizona Republic beginning in December triggered a congressional investigation. The newspaper reported that while few homes were built, key projects that were built were never occupied or had severe problems.

According to a review by U.S. Sen. John McCain's office and the Senate Indian Affairs Committee, the housing authority over 10 years received more than $803 million in federal block grant funding and built only 1,110 homes

The Republican senator from Arizona said in June that the authority's poor administration of grant funds exposed the housing program to excessive risk of waste, fraud and abuse.

"Until meaningful reforms are made to the way NHA does business, Navajo families will continue to suffer under housing shortages," McCain said in a statement Tuesday night. "I will continue to exercise rigorous oversight of NHA in my capacity as a member of the Senate Committee on Indian Affairs to ensure the Navajo people receive the housing they have been promised."

Housing authority board members and other Navajo officials have argued that the federal funding was not dedicated only for the completion of new homes as the calculations suggested.

They said the money also covered ongoing projects, the modernization of nearly 880 older homes over a four-year period along with infrastructure projects, land acquisitions, maintenance of existing homes and rentals and the construction of group homes and other community resource centers.

Navajo officials also have cited the unique challenges of building on a reservation that spans more than 27,000 square miles (70,000 square kilometers) over multiple jurisdictions in New Mexico, Arizona and Utah.

From the lack of basic utilities to complicated land ownership issues, the challenges have been well documented in recent years by federal housing officials and investigators with the U.S. Government Accountability Office.

The tribe also is plagued by high unemployment and poverty rates as well as a lack of infrastructure, from roads to internet connectivity.