Boston Mayor Michelle Wu defended the city's approach to immigration enforcement, and called for congressional action to address problems with the nation's immigration system, as she and other mayors faced an intensely partisan congressional hearing Wednesday.

During more than five hours of questions and political statements Wednesday, Wu and a trio of other mayors targeted by Republicans repeatedly argued they do not violate federal law by limiting local law enforcement interactions with federal immigration authorities.

The theatrical hearing reflected enormous tensions as President Donald Trump continues a major crackdown on undocumented immigration, with Democrats and Republicans sparring over the course of proceedings.

Wu on several occasions urged Congress to approve comprehensive immigration reform legislation, an idea that had momentum in 2024 before it was derailed by Republicans and some Democrats.

"Please, pass comprehensive immigration law that is consistent and compassionate. That will make our jobs possible, and we would so appreciate that partnership," Wu told lawmakers on the U.S. House Oversight and Government Reform Committee.

U.S. Rep. Paul Gosar, an Arizona Republican, asked mayors how to achieve comprehensive immigration policy "when you're defying it from the very get-go," alleging that their cities effectively shield people without legal status from deportation efforts.

"Respectfully, Congressman, you could pass bipartisan legislation, and that would be comprehensive immigration law," Wu replied. "The false narrative is that immigrants in general are criminals, or immigrants in general cause all sorts of danger and harm. That is actually what is undermining safety in our communities. If you wanted to make us safe, pass gun reforms. Stop cutting Medicaid. Stop cutting cancer research. Stop cutting funds for veterans. That is what will make our city safe."

Wu was joined by New York City Mayor Eric Adams, Denver Mayor Mike Johnston and Chicago Mayor Brandon Johnson.

After opening statements from mayors, committee members took turns -- alternating between Republicans, who were mostly critical of the mayors, and Democrats, who were mostly supportive -- asking questions and presenting their own views about immigration enforcement.

In Massachusetts, immigrants have accounted for a big share of the state's population and labor force growth over the years. More recently, an influx of migrants fleeing conditions in their home countries have swamped the state's emergency family shelter system, forcing the state to overhaul eligibility in a bid to control costs.

Wu described Boston's strengths as "not in spite of our immigrants, but because of them."

She called the state's capital "the safest major city in the country" thanks to its gun laws, relationships police have built in the community, and local faith in first responders -- all of which she said the Trump administration is "undermining."

"This federal administration is making hard-working, tax-paying, God-fearing residents afraid to live their lives," Wu said. "A city that's scared is not a city that's safe. A land ruled by fear is not the land of the free."

U.S. Rep. James Comer of Kentucky, the panel's Republican chair, argued that Congress should restrict federal funding to so-called sanctuary cities.

"President Trump and his administration are taking action against sanctuary cities, and Congress must follow not by allowing a single penny of federal funding to go to cities and states that prioritize criminal aliens over the American people," he said.

The hearing highlighted the partisan divide over what "sanctuary city" status entails.

Republicans argued that the four mayors lead municipalities where local policies shield people without legal status from immigration enforcement. U.S. Rep. Andy Briggs, an Arizona Republican, alleged that each of the four mayors "is exposed to criminal culpability" over failure to comply with federal enforcement efforts. Republican U.S. Rep. Nancy Mace of South Carolina told the mayors, "You all have blood on your hands."

Republican Congresswoman Anna Paulina Luna of Florida called out Boston's Trust Act, which limits local police from working with U.S. Immigrations and Customs Enforcement on civil immigration efforts.

Limiting police communication with federal immigration authorities about someone's immigration status violates federal law, Luna alleged, prompting Wu to reply, "That is not the truth."

As she wrapped up her questioning, Luna said she planned to refer all four mayors to the U.S. Department of Justice for investigation.

"I'm not doing that in an effort to bully you guys, but I do believe that your policies are hurting the American people, and you can make that known with the evidence that you can present to the Department of Justice," Luna said. "If you guys continue doing what you're doing, you're not going to help anyone. You're going to hurt more people."

Mayors did not directly answer yes or no when asked if they view their homes as sanctuary cities, with Wu replying that Boston is "a safe city." They also argued that their municipalities each follow federal, state and local law, and said immigration enforcement falls to the federal government under the Constitution.

"What Republicans are calling 'sanctuary cities' simply means that a city or a state is not going to do the job of ICE for them. That's it," said U.S. Rep. Summer Lee, a Pennsylvania Democrat. "Republicans are acting like there's like a mythical barrier that keeps ICE completely out of cities. If you're listening to Fox News, they make it seem like there's police at the borders of Chicago keeping ICE agents out, and that's simply not the case. Republicans want every town, city, state to dedicate their limited resources to entering what's called a 287(g) agreement with ICE to either do their enforcement work on the ground or hold people in custody for an additional 48 hours on detainers. That's 48 hours beyond the lawful detention."

U.S. Rep. Ayanna Pressley of Massachusetts, a former colleague of Wu's on the Boston City Council, also invoked Fox News during a defense of her hometown.

"It's clear my colleagues across the aisle didn't do their homework because the fears and division they're trying to project onto Boston are really the stuff of Fox News fever dreams," Pressley, a Democrat, said. "Our city is vibrant, our city is diverse, our city is beautiful."

Pressley and Comer, the committee's Republican chair, raised their voices at one another as tensions flared.

Pressley asked for unanimous consent to enter several news articles into the record. Comer said they would indeed be entered before Pressley finished reading the headlines and describing each article, and when she continued speaking, Comer attempted to cut her off and move on to the next lawmaker up for questions.

"This trend of you all trying to get thrown out of committees so you can get on MSNBC is going to end. We're not going to put up with it," Comer said.

Pressley argued that Comer should not "get to dictate how I recite the articles for the record."

Several Democrats zeroed in on Adams, pressing New York's mayor on the federal corruption charges against him and the circumstances behind the Trump administration's push to drop that case.

U.S. Rep. Robert Garcia, a California Democrat, displayed an image of Adams appearing on "Fox and Friends" alongside Trump border czar Tom Homan, who described a "commitment" between himself and the mayor.

"Are you selling out New Yorkers to save yourself from prosecution?" Garcia asked.

"There's no deal, no quid pro quo, and I did nothing wrong," Adams replied.

Homan in recent months has made a point to target Wu, at one point pledging he would be "bringing hell" to Boston as he sought to crack down on undocumented immigration.

"Shame on him for lying about my city, for having the nerve to insult our police commissioner, who has overseen the safest Boston's been in anyone's lifetime. Bring him here under oath and let's ask him some questions," Wu said about Homan at the hearing. "I am here to make sure that the city of Boston is safe. Others may want to bring hell. We are here to bring peace to cities everywhere."