Mayors from "sanctuary cities" across the United States are standing their ground after President Donald Trump signed an executive order on Wednesday that threatens to stop them from receiving federal funding.

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Generally speaking, a sanctuary city is a jurisdiction that has passed policies meant to protect undocumented immigrants. That typically entails restricting the ability of local law enforcement to detain people on the basis of their immigration status. In some cities, police are also prohibited from turning over undocumented immigrants to federal authorities.

Trump has repeatedly linked undocumented immigrants to criminal activity in the U.S., despite the fact they are statistically less likely to commit crimes than natural-born U.S. citizens. In September, he said sanctuary cities that protect these immigrants "will not receive taxpayer dollars." He seemed to follow through on that promise Wednesday, signing an executive order that would strip unspecified federal grants from these jurisdictions.

White House press secretary Sean Spicer said the president directed the U.S. Department of Homeland Security to identify possible grants "and then figure out how they can be cut off."

Mayors of sanctuary cities have already responded defiantly, vowing to uphold their immigrant-friendly policies.

1. Los Angeles

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"An open, welcoming, and compassionate spirit is not just an ideal that we try to live up to — it's part of the American character," Los Angeles Mayor Eric Garcetti said in a statement provided to ATTN:. "Those are our values in Los Angeles, and we intend to preserve them no matter what happens in Washington, D.C."

He continued: "Splitting up families and cutting funding to any city — especially Los Angeles, where 40 percent of the nation’s goods enter the U.S. at our port, and more than 80 million passengers traveled through our airport last year — puts the personal safety and economic health of our entire nation at risk. It is not the way forward for the United States."

California state Sen. Scott Weiner said the executive order merely "strengthens my resolve to stand up against the alarming bigotry and hatred emanating from the White House."

2. New York City

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"We are doing the right thing. We have a city that is working economically, that is more harmonious and that is safer," New York Mayor Bill de Blasio said at a press conference on Wednesday. "It’s working. We’re not going to deviate from that."

3. Chicago

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"I want to be clear," Chicago Mayor Rahm Emanuel told reporters on Wednesday. "We are going to stay a sanctuary city."

"There is no stranger among us," Emanuel said. "We welcome people — whether you’re from Poland or Pakistan, whether you’re from Ireland or India or Israel and whether you’re from Mexico or Moldovia where my grandfather came from. You are welcome in Chicago as you pursue the American dream."

4. Philadelphia

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"Given that today’s [executive order] was simply a directive and did not even make clear if there were any significant funding streams that the Trump administration could cut off to Philadelphia, we have no plans to change our immigration policy at this time," a spokesperson for Philadelphia Mayor Jim Kenney told Philly.com.

5. San Francisco

"We’ve been listening to the different pronouncements coming from President Trump and I have to say that there is nothing that has changed,” San Francisco Mayor Ed Lee said at a press conference on Wednesday. “Our city is still a sanctuary city.”

Though questions remain as to what specific federal grants Trump intends to cut, civil rights advocates expect sanctuary cities to prevail. 

"President Trump is threatening to punish localities for establishing constitutional safeguards and for protecting the public safety of their entire communities," Omar Jadwat, director of the ACLU's Immigrants’ Rights Project, said in a statement. "He may hope that local officials will buckle under his threats, but they have been preparing to defend their policies and we will stand with them in court."