The Boston Phoenix will cease publication of both its print and online editions, but its spin-offs in Portland and Providence, R.I., will continue to operate, according to the parent company of the weekly newspapers.

Stephen M. Mindich, the publisher, chief executive officer and chairman of The Phoenix Media/Communications Group, made the announcement at a staff meeting of the 47-year-old Boston newspaper Thursday.

Mindich’s statement said there would be “necessary changes” to the Portland Phoenix and the Providence Phoenix. However, Peter Kadzis, the executive editor of The Phoenix Media/Communications Group, said there are no plans for layoffs or significant alterations to operations in Portland.

Kadzis said Mindich’s statement indicated that some changes in job functions likely will result from closing the larger Boston publication and switching to a smaller organization supporting just the Portland and Providence papers. He said specifics on those changing job functions have yet to be worked out.

Mindich said the Portland and Providence Phoenix publications have been performing better financially than their Boston counterpart.

“Because of their smaller scale of operations and because we believe that they remain meaningful publications in their communities,” the Rhode Island and Maine publications will continue, Mindich said. He said they will continue “as long as they remain financially viable.”

Mindich said the Boston Phoenix was hit by changes in the media industry and the financial crisis that began in 2007. It has faced “significant financial losses,” Mindich said, and, along with a radio station the company owns, is “no longer sustainable.”

The company said Friday’s issue will be the last print issue of the Boston Phoenix. The last online issue will be posted on March 22.

Edward D. Murphy can be reached at: 791-6465

emurphy@mainetoday.com