The mayor has made her beliefs clear: The fate of a vacant school building on prime real estate in Northwest Washington represents the latest gentrification fight in a city full of them.

Mayor Muriel E. Bowser’s (D) proposed fiscal 2020 budget includes more than $100 million to relocate a top high school that serves a mostly black student body to the site of an empty middle school in Shaw — a gentrified neighborhood experiencing a baby boom. But the proposed move of Benjamin Banneker Academic High School has sparked opposition from Shaw families, who say they were promised a standalone middle school on that site.

At a news conference Monday, D.C. Council Chairman Phil Mendelson (D) announced that he would side with the Shaw families and move to strip funding from the council’s proposed budget to relocate the high school, intensifying a fight between the Banneker and Shaw communities. They both say that the property in the 900 block of Rhode Island Avenue NW was promised to them.

Mendelson said his budget would include money to renovate Banneker at its current site, in the 800 block of Euclid Street NW in Columbia Heights.

“The fact of the matter is that the area around Shaw Middle School has been promised a new middle school for a decade,” Mendelson said.

Bowser’s administration says the site in Shaw would allow Banneker, which serves nearly 500 students, to increase enrollment by 300. The administration says its projections do not show that the Shaw neighborhood has enough students to support a standalone middle school.

Seven of the 13 D.C. Council members signed a letter last week saying they supported renovating Banneker instead of moving it to Shaw. That would allow the empty Shaw Junior High School, which closed about a decade ago amid declining enrollment, to reopen.

The D.C. Council is scheduled to vote Tuesday on its version of the budget, which includes money to build a middle school for Shaw.

Bowser did not mince words in responding to the council.

“After weeks of protests in Shaw against gentrification and displacement, I am shocked that seven council members have signed onto a letter telling the students, families, and staff at Benjamin Banneker High School — which was once again ranked by U.S. News & World Report as one of the best high schools in the nation — they need to stay put in their current location,” Bowser wrote in a letter Friday to council members.

Banneker is among the city’s top-performing high schools, attracting high-achieving students from across the District. The Banneker student body is about 95 percent black and Hispanic. Twenty percent of students are considered at risk, which means they are homeless, receive welfare or food stamps, are in foster care or have been held back at least a year in school.

City figures show 100 percent of Banneker’s at-risk students graduate from high school. Citywide, 46 percent of students are considered at risk, and about 59 percent of those students graduated in four years.

Nearly 800 eighth-graders applied for slots in next year’s 170-student freshman class at Banneker, according to city data.

“More students from Ward 8 should be given the opportunity to come to Banneker,” said senior Diavionne Newell, referring to the ward in Southeast Washington where she lives and which has a high concentration of low-income residents. “When I go to Banneker, I get to get away from my community, but I also get to give back to my community.”

The Shaw families rejected the mayor’s framing of the future of Shaw Junior High as a gentrification flash point. The Shaw families have placed “Save Shaw Middle School” signs on yards and distributed fliers about the need for the school. Banneker students and Shaw families have made their case through protests in recent days at City Hall.

Alex Padro, an advisory neighborhood commissioner in Shaw, said the five elementary schools that would feed into a Shaw middle school are diverse and growing with large populations of students from low-income families. Families at these schools, he said, find their current middle school inadequate and might flee the neighborhood or the school system if the city does not reopen Shaw Middle, he said.

Middle-schoolers from Shaw go to Cardozo Education Campus, which serves students in middle and high school. About 160 middle school students are enrolled there.

Padro said Cardozo is a low-performing school and many families do not want to send their children to a campus with high school students.

“For anyone to say that this is a gentrification issue is totally unconscionable and is not supported by facts,” Padro said. “Muriel Bowser has been throwing these communities against each other.”

The old Shaw Junior High sits on an expansive piece of property that has a field and a dog and skate park. The field has been closed to build the new campus.

Paul Kihn, the city’s deputy mayor for education, said he expects enough space to remain for the dog and skate parks if the neighborhood wants them. He said the campus would allow Banneker to have space for sports and other activities, which the Columbia Heights school lacks. The school sits on public land that includes a track, pool and field, although the school does not have priority use of it.

Kihn said the city would consider opening a standalone middle school at Banneker or at a closed middle school at 10th and V streets NW. He said a city analysis does not support the need for Shaw Middle School, given empty seats at Cardozo.

“Do we need additional middle school capacity given the relatively low projections of middle school enrollment across the city?” he said.

Mary Filardo, executive director of the 21st Century Schools Fund, a D.C. nonprofit group that analyzes school facilities throughout the country, said she has studied population growth in Shaw and thinks demand exists for a middle school.

She said the city should enable Banneker to use the adjacent recreation space so it can have the facilities it needs.

If the city builds a robust middle school in Shaw, Filardo said, she is confident that students will enroll.

“What I don’t understand,” she said, “is why the school system does not have more confidence in itself.”