City Councillor at-Large Ayanna Pressley says she will challenge incumbent U.S. Rep. Michael Capuano for his 7th district congressional seat later this year, setting up a rare showdown between two popular Massachusetts Democrats with strong progressive credentials.

Capuano is presently serving his tenth term as representative for the district, serving parts of Boston, Cambridge, and Milton, as well as Chelsea, Everett, Randolph, and Somerville. Capuano, 66, has never faced a serious election re-election challenge for the Congressional seat that he won in a hotly-contested 1998 election to replace former Rep. Joseph Kennedy II. The former mayor of Somerville, he is the delegation’s senior member of two key Congressional committees: Transportation and Infrastructure and Financial Services.

In a statement, Pressley said the country is “facing a critical moment” and pledged to be a bold voice in Congress.

“This district and these times demand more than just an ally, they demand an advocate and a champion,” she said.

“These issues that we are facing are not new,” Pressley, 43, told the Reporter Tuesday, pointing to issues ranging from housing to development.  “They are exacerbated by what is coming out of the White House,” she said.

Pressley, a Dorchester resident, was elected to the council in 2009 as the first woman of color to serve in the municipal legislative body. She highlights several key advocacy areas during her time on the council — creating pathways to economic development and employment in historically underserved communities, ensuring students have access to age-appropriate and medically accurate health education, and transforming how Boston responds to violence and trauma — as translating to the broader congressional district’s needs.

“My life as an advocate for those most in need is inspired by my mother’s example. She believed in the potential inherent in each of us, and that belief is the foundation of my work,” Pressley said in a statement.

“I’m ready to take my fight higher and farther,” she said.

Pressley described her decision to run as a thoughtful process and said that she is looking forward to hearing from the district.

As a city councillor-at-large, Pressley has been representing a large chunk of the 7th Congressional District in City Hall for the past eight years. If elected, Pressley plans to approach policy making similarly to how she has as councilor, by working in partnership with the community to develop solutions.

“This is a district that I want to fight for. Ultimately, it’s about this district…it’s bigger than Ayanna Pressley or Michael Capuano,” she said.

“I think my job is to gauge the temperature and set the temperature [through policy],” she said, pointing to her work as a councillor to ensure that students received quality food at school and her advocacy for early education and childcare for non-traditional workers.

If elected, the list of issues that she would want to tackle is long, Pressley said, but she will continue to be an advocate for reproductive justice, work to repeal the Hyde Amendment, and tackle gun control— among others.

Pressley was re-elected to her council seat last last November. If she leaves the council post, her departure would usher in former state representative and fifth-place at-large finisher Althea Garrison to fill her vacancy.

News of Pressley’s decision to challenge Capuano has been bubbling in political circles for weeks. Politico’s Lauren Dezenski reported on Wednesday that an internal poll conducted by Pressley’s team last December helped cement her decision to run. According to Dezenski, Capuano maintains a “significant lead on a generic Democrat for his re-election.” But, she reports that the poll indicated that when voters learned more about Pressley, “Capuano’s lead went down to 7 points.”

In a brief Facebook posting on Tuesday, Capuano stated: “This election is a great opportunity to highlight my aggressive progressive record, opposing Trump and standing up to Republicans in Washington. I will never stop fighting for the interests of my constituents. See you on the campaign trail!”

Eileen Boyle from Dorchester’s Ward 15 Democratic Committee said that she was not surprised when she heard that Pressley was throwing her hat in the ring for congressional office, since she assumed that the councillor had ambitions for higher office.

“It’s always good to have different people stepping up,” said Boyle. “I just want people in office that have been up-front with us.”

Boyle said that she would like to see Pressley do more to address housing and transit issues.

Former City Councillor Charles Yancey, who worked with Pressley on the council, wished the councillor well. Yancey, a Dorchester resident, ran twice unsuccessfully for Congress from City Hall, including a 1998 candidacy in an election that ended in Capuano’s victory.

“I think that if she’s interested she should just pursue it and not wait for other’s permission if she feels that she can add something positive,” Yancey told the Reporter.

Former state Rep. Marie St. Fleur, who represented the Fifth Suffolk district from 1999-2011 told the Reporter on Wednesday that challenges to incumbents are healthy.

"[Capuano] has served the district well,” said St. Fleur, a Dorchester resident who also lives in the 7th Congressional district. “In terms of constituent services, he has been terrific,” as has been his handling of Haitian-specific concerns, she said. "That's not this issue."

"The seats do not belong to those who currently hold them,” St. Fleur said. “The seats belong to the people. I don’t believe in term limits, so every election cycle is your term limit… if you say ‘I’m not for term limits,’ then races should be contested."

St. Fleur said potential challengers to Capuano have weighed their own runs before, but deferred to him “out of respect.”

But “19 years in, Boston has changed,” she said. “Any company that’s been around for 20 years should look at its staff to see if there are chances for new directions, staff, and opportunities,” she said. “Ayanna Pressley provides that. There are no people of color in the congressional delegation, yet increasingly [the Massachusetts’ Seventh] is the only district that is majority-minority in the state. It is appropriate that a person of color takes a serious look at it.”

Pressley has been considering a run for congress for years, said former state Rep. Charlotte Golar Richie.

"I would imagine she’ll be a formidable candidate," Golar Richie said. "I've already heard from supporters of hers who were there with her when she made history [when elected to the council]. She made history then and she has a loyal following of supporters who would love to see her make history again."

The 7th district’s boundaries were redrawn in 2011 when Massachusetts downsized from 10 districts to nine. Candidates must submit nomination signatures to clerks by May 8, with 2,000 certified signatures required to ensure ballot access. The primary election this year is Sept. 4 and the state election is Nov. 6.

State House News Service material and Reporter news editor Jennifer Smith contributed to this report.