Minneapolis Mayor Jacob Frey is endorsing Don Samuels in his DFL primary race against Rep. Ilhan Omar. (Aaron Lavinsky, Star Tribune file/The Minnesota Star Tribune)

Minneapolis Mayor Jacob Frey on Thursday endorsed Democrat Don Samuels' primary election bid to unseat U.S. Rep. Ilhan Omar, backing the congresswoman's challenger after she supported his mayoral opponents last year.

Samuels, a former member of the Minneapolis city council and school board, is seeking to defeat Omar in Tuesday's DFL primary election in Minnesota's Fifth Congressional District, which includes Minneapolis and eastern Hennepin County. Omar beat her last well-funded Democratic primary challenger by about 20 percentage points two years ago.

"As our city and nation navigate great challenges, we need partners across all levels of government who prioritize teamwork, collaboration, and a seriousness of approach to match the seriousness of the issues we face," Frey said in a statement about his choice of Samuels. "This is an endorsement for someone who's shown an ability to do just that."

Omar endorsed two of Frey's mayoral challengers last year and encouraged Minneapolis voters not to rank him on their ballots. The Democratic congresswoman also supported a ballot measure to replace the Minneapolis Police Department with a new Department of Public Safety, which Frey opposed. Minneapolis voters rejected the proposal 56-44%.

Samuels is a longtime north Minneapolis resident and gun violence prevention advocate. He was among those leading the push for more police amid an uptick in violent crime in Minneapolis, filing a lawsuit arguing the city needed to increase police staffing levels because it wasn't meeting minimum requirements outlined in the city's charter. He lost a run for mayor in 2013.

In addition to Frey, Samuels' campaign announced endorsements from the mayors of St. Louis Park, Golden Valley, Edina and New Hope on Thursday. Other Samuels endorsers include former Minnesota Secretary of State Joan Growe and five former state DFL Party chairs.

"I am honored by the endorsements of such distinguished leaders in the Fifth District," Samuels said in a statement about the mayors backing him. "The mayors' endorsements today come from leaders who know the importance of all levels of government working in tandem to get things done."

The first Somali American elected to Congress, Omar is seeking her third term representing the reliably Democratic Fifth District. Her outspoken approach, echoed by other members of the progressive "Squad" she is part of, often conflicts with her more moderate colleagues and draws scrutiny from Republicans.

In a statement Thursday, Omar did not address Frey's endorsement, instead touting the many local elected officials who support her. Among those her campaign listed was DFL Senate Minority Leader Melisa López Franzen, who told the Star Tribune she has not yet made an endorsement in the race. Samuels also recently listed an endorsement from a local pastor who had not publicly backed him.

Omar has been endorsed by the Minnesota DFL Party, Attorney General Keith Ellison, nearly two dozen state lawmakers, several Minneapolis City Council members and the mayors of Robbinsdale, Brooklyn Center and Columbia Heights.

"I believe in co-governance, and together we will continue to fight for progress for everyone in the 5th District, regardless of ZIP code," Omar said.

Ellison praised Omar as an advocate for women's rights "at a moment when the Supreme Court is trying to take them away." He also commended her for supporting the ballot measure to replace the Minneapolis Police Department with a Department of Public Safety.

"I want us to have a truly trusting relationship between police and community, and that requires a reform-minded person," Ellison said in an interview. "And that's what Ilhan is."