WASHINGTON — Republican members of Congress hammered four Democratic mayors Wednesday about their so-called sanctuary city policies, accusing them of endangering Americans and threatening to prosecute local officials. The mayors pushed back, defending their communities as welcoming places — not lawless danger zones — and called on Congress to pass immigration reforms.

The comments came in an often fiery hearing before the House Committee on Oversight and Government Reform, where Republicans said the mayors were undermining President Donald Trump’s immigration and mass deportation efforts.

Republicans repeatedly highlighted a handful of brutal crimes committed by immigrants who crossed illegally into the U.S., with Rep. James Comer opening the hearings by saying the policies “only create sanctuary for criminals.”

But the Democratic mayors — Michelle Wu of Boston, Brandon Johnson of Chicago, Mike Johnston of Denver and Eric Adams of New York — defended their policies as legal, even as they seemed to carefully avoid using the term “sanctuary.”

Republicans, they said, were trying to paint their cities as overrun by criminal immigrants even as crime was falling. The mayors said a key to safety is creating cities where residents feel comfortable reporting crimes and working with police.

“We know there are myths about these laws. But we must not let mischaracterizations and fearmongering obscure the reality that Chicago’s crime rates are trending down,” Johnson told the committee in a hearing room packed with reporters and onlookers. “We still have a long way to go, but sensationalizing tragedy in the name of political expediency is not governing. It’s grandstanding.”

There’s no legal definition for sanctuary city policies, but they generally limit cooperation by local law enforcement with federal immigration officers. Courts have repeatedly upheld the legality of sanctuary laws.

Illegal immigration was a key plank of Trump’s presidential campaign, and he has repeatedly pressed on the theme since coming to office, including a Tuesday night speech to Congress where he vowed to “complete the largest deportation operation in American history.”

Republicans have largely echoed Trump.

“We cannot let pro-criminal alien policies and obstructionist sanctuary cities continue to endanger American communities and the safety of federal immigration enforcement officers,” Comer said Wednesday.

But Denver’s Johnston said that crime dropped when the city was faced with an influx of immigrants, many bused from border states by Republican politicians. Like the other mayors, he said the onus should be on Congress to update federal immigration laws.

“If Denver can find a way to put aside our ideological differences long enough to manage a crisis we didn’t choose or create, it seems only fair to ask that the body that is actually charged with solving this national problem — this Congress — can finally commit to do the same,” he said.

Adams got some of the only praise from Republican lawmakers, with Comer thanking him for working with Immigration and Customs Enforcement.

Adams’ critics say his collaboration is part of an effort to wriggle out of federal corruption charges, though even before Trump was elected, the mayor called on city lawmakers to allow New York police to work more with ICE. The Trump administration ordered prosecutors to drop the case against Adams on the grounds that it was distracting him from helping the immigration crackdown and hindering his reelection campaign.

Democratic lawmakers questioned him sharply over his work with the Trump administration and Justice Department orders to drop the charges.

“Are you selling out New Yorkers to save yourself from prosecution?” asked Rep. Robert Garcia of California.

“There’s no deal, no quid pro quo. And I did nothing wrong,” Adams said.

Immigration law, the mayors said, is a federal responsibility, and the attempt to put that responsibility on local law enforcement makes communities distrust the police and others they may need to call for help. Trump’s crackdown, the mayors said, has terrified immigrants, many of them in the U.S. legally.

“I spoke with pastors whose pews are half-empty on Sundays,” said Wu, whose parents immigrated to the U.S. from Taiwan. “Doctors whose patients are missing appointments, teachers whose students aren’t coming to class, neighbors afraid to report crimes in their communities, and victims of violence who won’t call the police.

“This federal administration is making hard-working, taxpaying, God-fearing residents afraid to live their lives.”

In communities that don’t cooperate on immigration, ICE agents go in to track down people after their release. ICE argues that this is dangerous and strains resources.