The mayor of a largely white, historically working-class Boston suburb has vowed not to remove a Black Lives Matter banner from City Hall despite complaints from police officers across the state.

Somerville Mayor Joe Curtatone, a white Democrat, said Thursday it's "OK to disagree" and the only way to resolve the impasse is through an "open dialogue" about race.

"That sign is not coming down," he insisted while standing in front of City Hall flanked by the police chief and two deputy chiefs.

The Somerville Police Employees Association and other police unions said they'd peacefully rally Thursday evening outside City Hall, where the sign has hung for nearly a year, to demand Curtatone remove it.

The local police union's president, Michael McGrath, said his officers support the "core goal" of the Black Lives Matter movement but believe the banner sends an "exclusionary message" and is disrespectful to officers.

"In the face of the continuing assassination of innocent police officers across the country ... it is irresponsible of the city to publicly declare support for the lives of one sector of our population to the exclusion of others," McGrath said in a statement this week.

Curtatone, the son of Italian immigrants and the mayor since 2004, has argued that standing up for minority residents and supporting police officers aren't "competing interests." He noted the city also has hung a banner over police headquarters honoring police officers slain in Dallas and in Baton Rouge, La.

"Both of those banners are hanging for the same reason: Too many people have died in a cycle of violence that needs to be stopped," he said in a statement.

When asked on Thursday whether he thought it was appropriate to place the Black Lives Matter banner on a government building, he replied: "No one can sit out this conversation. Where this is happening is in cities. This is the grassroots level."

Curtatone hung the 4-foot-by-12-foot banner over City Hall's main entrance in August 2015 at the request of a local Black Lives Matter chapter. At the time, he said it was meant to recognize that "structural racism" exists in society and stressed it was not a criticism of his police department.

The police banner hangs over the police headquarters entrance and says, "In honor and remembrance," with an image of the Dallas Police Department badge and a black band across it.

Curtatone has said he'll seek to equip his police officers with body cameras, something some civil rights activists have called for after police-involved killings. He also pledged to push the police department and other city agencies to conduct anti-racism training programs for their employees.

Last week, the city police union called on the mayor to replace the Black Lives Matter banner with one that states "All Lives Matter," a phrase some civil rights activists complain diminishes their concerns about the killings of black men and boys at the hands of police.

In response, police Chief David Fallon, who supports keeping the banner over City Hall, chided the union for getting involved in the debate.

Curtatone said opposition to the banner wasn't shared by all police officers. He also said he's "proud" of the response from residents, community leaders, faith-based leaders and activists, and he rejected the notion officers would face reprisals if they attended the rally.

Somerville is a city of more than 80,000 residents that borders Boston and Cambridge and is home to most of Tufts University's campus. It is about 74 percent white, 11 percent Latino, 9 percent Asian and 7 percent black, according to 2010 U.S. Census data.