OAKLAND — Accreditors have placed the Peralta Community College District's campuses on probation, saying the board of trustees and district administrators have put the schools at risk.

In a letter received Tuesday by Peralta leaders, the Accrediting Commission for Community and Junior Colleges wrote that it had significant concerns about "the fiscal solvency and stability" of the 46,000-student district. Peralta officials must demonstrate by October that they have solved most of the problems, the letter said.

The "deficiencies may jeopardize the accreditation of all the district's colleges," wrote Barbara Beno, president of the commission.

Schools must maintain accreditation to show they are meeting academic standards. Losing accreditation is the most serious sanction a college could face.

The Peralta document leveled heavy criticism at the board of trustees and the leadership of the district's recently departed chancellor, Elihu Harris. The district includes Oakland's Laney and Merritt colleges, Berkeley City College and the College of Alameda.

Commissioners said trustees have meddled in district affairs, especially in hiring decisions. A commission report, attached to the letter, noted concern over the hiring of Peralta's inspector general and the creation of a new vice chancellor's position to oversee human resources.

"The personnel hiring process appears to have lost its focus and integrity because of the involvement of a few members of the board of trustees," the report said without naming the involved trustees. "Concerns about board members interfering with the leadership of the chancellor ... raise questions about how effectively the district and its colleges can operate."

Commissioners also noted the significant financial and computer problems that have ravaged Peralta since Harris took over in 2003. One of Harris' early decisions — to switch the district to a PeopleSoft computer system that has never been fully understood by employees — has caused serious problems with the district's financial accounting and operations, accreditors said.

Those problems have prevented Peralta's auditors from completing their work for the past two years, leading to confusion about how much money the district spends.

"The fiscal integrity of the district has been severely compromised by the failure to correctly operate its financial accounting systems, but the actual fiscal state is unknown at this time," commissioners wrote.

Peralta's interim chancellor, Wise Allen, could not be reached Tuesday. Board President Abel Guillen and trustee William Riley did not return phone messages.

Matt Krupnick covers higher education. Contact him at 925-943-8246. Follow him at Twitter.com/mattkrupnick.