WASHINGTON — Sen. Dave McCormick is pushing Pittsburgh Mayor Ed Gainey to fall in line with stronger immigration enforcement as President Donald Trump and Republicans on Capitol Hill aim to crack down on undocumented migrants across the country.

Gainey, a Democrat, said Monday that his administration “will not work with (Immigration and Customs Enforcement)” and will instead do “whatever is necessary to make our city more welcoming.”

The statement came a week after Trump took the oath of office and quickly enacted hard-line policies that restrict entry into the U.S. and enable greater detention and deportation of undocumented immigrants.

McCormick, a freshman Republican aligned with Trump on immigration and border policy, urged the city's top elected official to reverse course.

“Pittsburgh Mayor Ed Gainey needs to follow the law and the lead of some other Democratic mayors who are working with law enforcement to keep our cities safe,” the senator posted on X. “Mayors will no longer get a pass for taking the law into their own hands — President Trump and his team will restore law and order in our nation's cities.”

The clash between the two is unfolding amid a growing national battle between Republicans in Washington who support Trump's hard-line policies and local elected officials in heavily Democratic cities who are pushing back against the new administration's dramatic moves.

The Republican-led House Oversight and Government Reform Committee has summoned four Democratic mayors — Boston's Michelle Wu, New York City's Eric Adams, Chicago's Brandon Johnson and Denver's Mike Johnston — to testify next month over their cities' so-called “sanctuary” status, which the GOP lawmakers cast as an “abject failure to comply with federal law.”

Gainey, who is up for reelection, told the Pennsylvania Press Club at a Harrisburg hotel Monday that Pittsburgh was built on a welcoming spirit.

“ICE is not going to end the situation of a failed immigration policy,” he said. “It's not going to do it. What it is going to do is create more situations where people feel scared. Where people don't feel safe. Where people do things they normally wouldn't do.”

He called on Congress to address immigration and a pathway to citizenship — a far cry from the barrage of executive orders and directives issued by Trump in the first week of his second administration.

The president has pledged to halt all illegal entry at the southern U.S. border, ordered the resumption of his previous policy forcing asylum seekers from Mexico to return to their country to await U.S. immigration court hearings, and ceased the so-called “catch and release” policy that allowed undocumented migrants to be released into American communities as they wait for their day in court.

Trump also attempted to drastically limit birthright citizenship — a right enshrined in the U.S. Constitution for more than 100 years — but a federal judge temporarily blocked that order.

Trump has said he'll continue to press to remove all undocumented immigrants — a pledge sparking concerns of increased roundups, family separations and economic turmoil.

McCormick has applauded Trump's “decisive action” on immigration, saying it would improve safety in Pennsylvania cities.

“This is not just a border state crisis,” he said last week. “More than 4,000 Pennsylvanians die each year from fentanyl overdoses, and the influx of illegal immigrants into Pennsylvania communities has put strains on public resources. These actions will end the mass-release of illegal immigrants into our communities, strengthen (Customs and Border Protection) enforcement at the border, crack down on sanctuary cities, and restart the wall to make it harder to cross illegally.”

Monica Ruiz, executive director of the Beechview-based advocacy group Casa San Jose, told the Post-Gazette her group is now reaching out to the city's migrant community to make people aware of their constitutional rights.

The effort comes amid rising fear within immigrant communities — including areas such as Brookline, Beechview and Charleroi — as rumors and alarm spread across social media this week.

“People forget that immigrants are people, too, and they have rights,” Ms. Ruiz said.

Several cities have already seen increased raids by ICE.

Over the weekend, ICE officials received instructions from the White House to ramp up deportations, from a few hundred per day to at least 1,200, The Washington Post reported.