Signaling the end to a quarter century career in Congress, Rep. Luis Gutierrez will announce Tuesday that he will not seek re-election, Democratic sources tell the Chicago Sun-Times.

The Northwest Side Democrat has been one of the more high-profile Latino politicians in the country, advocating forcefully for immigrant rights, since he became a U.S. representative 25 years ago.

Gutierrez, 63, planned to make his retirement announcement Tuesday in Chicago, the sources said.

He has a news conference scheduled for Tuesday afternoon at Maggiano’s Little Italy restaurant.

The sources added that Cook County Commissioner Jesus “Chuy” Garcia, D-Chicago, likely will run to succeed Gutierrez in next year’s election with Gutierrez’s endorsement. The sources said 22nd Ward Ald. Ricardo Muñoz was expected to run to replace Garcia on the Cook County Board of Commissioners.

Gutierrez and Garcia are scheduled to appear at a campaign kickoff event for Garcia at Mi Tierra restaurant in Little Village — Garcia’s neighborhood — at 6 p.m. Tuesday.

Neither Gutierrez and Garcia returned calls seeking comment Monday.

Ald. Carlos Ramirez-Rosa (35th) is also considering making a run for Gutierrez’ congressional seat, sources said.

Before becoming a congressman, Gutierrez was an alderman allied with then-Mayor Harold Washington during the “Council Wars” period at City Hall in the 1980s.

Known as “El Gallito” (Spanish for “The Little Rooster”) for his slight build and combative political style, Gutierrez also has been a major player for decades in the long-running debate over the future of Puerto Rico, his ancestral homeland.

He owns an oceanfront townhouse in Puerto Rico.

His 4th Congressional District, which was drawn to better represent the Chicago area’s growing Hispanic communities, includes many neighborhoods and inner-ring suburbs with large Mexican and Puerto Rican populations.

He said he would retire a decade ago, sparking fierce jockeying to represent his district, but quickly reversed that decision and continued to serve in Washington with little real opposition to his re-election campaigns.

Gutierrez filed nominating signature petitions to run again Monday, but the sources said he would pull that paperwork Tuesday.

Gutierrez’s endorsement of Garcia will mark a return to the congressman’s roots in the city’s independent political circles.

For decades, Gutierrez has moved repeatedly between the establishment and left-leaning wings of the Chicago Democratic Party.

After being a key part of Washington’s multi-racial, independent coalition, Gutierrez later allied with Mayor Richard M. Daley.

He flirted with challenging Daley in 2007, criticizing him sharply, only to end up endorsing him.

And despite fighting publicly for years with Rahm Emanuel over immigration policy, Gutierrez endorsed Emanuel over Garcia in the 2015 mayoral election, when Garcia forced a runoff vote.

Gutierrez, along with a handful of Democratic congressmen, filed articles of impeachment on Nov. 15 against President Donald Trump.

“My office in Washington has been getting two types of calls in reaction to the articles of impeachment: encouraging, supportive calls mostly from people in and around Chicago and then the usual angry calls, mostly from people nowhere near Chicago. My constituents are mainly asking ‘what took you so long?’” Gutierrez said.

Contributing: Lynn Sweet