Sanctuary cities are refusing to back down in the face of the Trump administration’s crackdown on immigration, which was codified on Monday after Attorney General Jeff Sessions threatened to cut off funding for states and cities that shelter undocumented residents.

Officials from many of those jurisdictions met in New York on Tuesday to discuss how to fight the plan—the second consecutive day of brainstorming from leaders of some of the country’s biggest urban centers, as Reuters noted. The strategy session brought in attendees from California, Connecticut, Pennsylvania, Texas, Washington state, Wisconsin, and elsewhere.

It was preceded by the Center for Popular Democracy (CPD), a left-leaning advocacy group, releasing a guide and toolkit on protecting undocumented immigrants. The blueprint, published last week, aims to help local-level policymakers “create or further strengthen sanctuary style laws and policies.”

That call is widespread these days.

As New York City Mayor Bill de Blasio tweeted Monday night, “The Trump administration is pushing an unrealistic and mean spirited executive order. If they want a fight, we’ll see them in court.”

Seattle Mayor Ed Murray added, “[W]e stand resolute. Trump’s immigration policy is based in bigotry not safety.”

California’s Senate President Pro Tem Kevin de León called the plan “nothing short of blackmail” and warned, “Withholding federal resources is unconstitutional. We’ll not hesitate to fight him, and settle the matter in court.”