Mayor Martin Walsh is endorsing US Rep. Michael Capuano in the Democratic primary for the Massachusetts Seventh Congressional District, where the 10-term incumbent is facing a challenge from City Councillor At-Large Ayanna Pressley.

In a statement released Saturday, Walsh said, “Mike is one of the strongest champions for working people and urban communities in all of America.”

“As Mayor of Boston, I’m not about to give that up,” he said. “Not by a long shot. Mike's record is strong, and continues to grow stronger. You can see his record for yourself – just take a look around our city and you'll see evidence of Mike's years of advocacy and hard work as a Congressman. Mike has brought vital funding and transformational projects to places of our city that need it most."

Though there is scant daylight between their policy positions, Pressley says she will bring a new lens to Congress. The 44-year-old Pressley, who lives in the Ashmont village of Dorchester, has been avid in pushing for more compassion and resources for vulnerable and historically underserved populations.

Capuano, 66 years old and the former mayor of Somerville, has staked out ground on a generally progressive voting record and billed himself as a bridge-builder with other members of Congress.

The district includes most of Boston, parts of Cambridge and Milton, and all of Chelsea, Everett, Randolph, and Somerville. It is the state’s only majority-minority congressional district -- a notable feature with the Democratic primary shaping up between a black woman and an Irish-Italian man.

Capuano told the Boston Globe he and Walsh “see the road pretty much the same.”

“It sends a signal to everyone that the mayor and I are working very hard together to fight for them,” Capuano told the Globe. “I think it’s important to see that people of like minds stick together.”

They plan to formally announce the endorsement Sunday afternoon, 3 p.m., at 535 Columbia Rd. in Uphams Corner.

Wilnelia Rivera, senior advisor to the Pressley campaign, said in a statement that the campaign is focusing on engaging with voters.

"Over the past few weeks, we have heard the encouraging voices of support from people in this district who see themselves in this campaign," Rivera said, "from union hotel workers and electricians in the City of Boston to grassroots community leaders in Chelsea and Cambridge and countless others, including many who have chosen this moment to be involved in politics for the first time. Their stories, and the urgency of their challenges that too often go unheard, is what continues to propel this campaign forward."