Closing branch libraries should be the city’s “last option” and should follow an extensive review of Boston Public Library finances and “lengthy” public debate, nine city councillors wrote in a letter to Boston Public Library President Amy Ryan.

“The Boston City Council has faith in President Ryan’s leadership and we believe that the men and women who run and work for our libraries do so for all the right reasons – for love of service and learning,” the councillors wrote. “But we cannot support the plan to close libraries after so short a discussion period.”

The nine members of the 13-member council who signed the letter, dated April 2, included: President Michael Ross, City Councillors At Large Felix Arroyo, John Connolly and Ayanna Pressley, and Councillors Sal LaMattina (District 1), Charles Yancey (District 4), John Tobin (District 6), Chuck Turner (District 7), and Mark Ciommo (District 9).

In response, Dot Joyce, a spokeswoman for Mayor Thomas Menino, said, “Engaging in a debate about process is simply a tactic used to distract from the very difficult issues of how best to deliver quality library services to all of our residents.”

She added: “The Mayor has always been a staunch supporter of libraries. As a young man the Mayor used to go to his neighborhood branch with friends to study. He very much understands the value of our branches but also understands the need to change how we do business so we can serve more people, with better resources for more hours of the day.”

The councilors said in the letter they believed library officials need to “broaden the level of public input and participation, and search for alternatives to library closings.”

“The citizens of Boston are innovative and resilient,” they wrote. “We cannot make a decision that will affect the lives of Bostonians for years to come in only a few short months.”

The councillors also called for library trustees to "incorporate fundraising as a core function of its many duties." "Board members should be able to help facilitate donations, bringing new revenue into the system when it needs it most," they wrote.

The letter comes as trustees, weighing ways to tackle a $3.6 million budget gap, are expected to decide Friday what their next steps are.

City Councillor At-Large Stephen Murphy said the city’s budget process should be allowed to play itself out over the next several weeks, adding that the library system should not be used as a "political football."

“I don’t generally sign letters,” he said, adding, “I’m supportive of finding a way to keep the libraries open.”

While some of his colleagues have called for the city to dip into its reserves to cover the budget gap, “let’s see what the reserves are at first,” Murphy said.

Murphy noted that the sale of the Caritas Christi system, which includes Carney Hospital in Dorchester, is expected to bring in tax revenue to city coffers. “We may well not have to do any of that stuff,” he said of closing libraries.

The trustees first meet on Wednesday, at 8 a.m. at the Copley branch, for further discussions with Ryan about the fate of the library branches.

Seven branches are located in the Dorchester and Mattapan area: Lower Mills, Adams St., in Codman Square, Fields Corner, Grove Hall, Uphams Corner, and the branch on Blue Hill Ave. in Mattapan. Already protected from closure and cutbacks, according to the Boston Public Library, are the following branches, dubbed “lead” libraries: Codman Square, Mattapan, Grove Hall, Brighton, Dudley, Honan-Allston, Hyde Park, and West Roxbury.