NEW YORK (CBSNewYork) — New York City leaders are firmly against President Donald Trump‘s plans to cut off millions of dollars in federal funding to sanctuary cities.

Borough President Ruben Diaz, Jr. believes the Bronx will be hardest hit by Trump’s sanctuary order, pointing out that over 40 percent of the 1.4 million people in the borough come from other countries.

“President Trump, you should open your eyes and see what the real story is here, and the real contributions of those who come from other countries, and the work and the value that they add to the Bronx, our city, your city,” Diaz said Thursday. “This is not alternative facts, this is reality, the immigrant population in our borough has made us a whole lot better.”

The fear is that programs will be decimated, 1010 WINS’ Juliet Papa reported.

U.S. Rep. Adriano Espaillat (D-N.Y.) plans to mobilize, vowing court action to challenge the president’s orders.

“We will go to court, we will march, we will do anything that we have to do,” he said. “This is un-American and we will do anything to preserve our nation.”

On Wednesday, Mayor Bill de Blasio said the loss of funds would cut the resources of the NYPD — including anti-terrorism funding — and damage relations between police officers and communities. He added that the city would not begin deporting law-abiding undocumented immigrants because of the order.

De Blasio also said the executive order is written in a “very vague fashion,” and expected that it would be susceptible to legal challenges and public resistance.

In New Jersey, the mayors of Newark and Jersey City say they’ll continue to do all they can to protect residents from deportation, WCBS 880’s Kelly Waldron reported.

Ari Rosmarin of the ACLU of New Jersey says the president’s executive order raises major legal issues.

“Cities and county’s across the country are not obligated to help Trump with his immigration enforcement plan,” Rosmarin said.

He also said it would only hurt already strained relations with the police and the communities they protect.

“When cops get into the business of becoming an immigration agent, trust and public safety break down,” Rosmarin said.