America’s leading mayors have been teeing up resources in anticipation of helping those targeted by immigration raids slated to start on Sunday.

After Trump first announced the raids last month, officials in a handful of the nine major cities being targeted – Atlanta, Baltimore, Chicago, Denver, Houston, Los Angeles, Miami, New York and San Francisco – came out against the announcement and affirmed their support for immigrants in their cities.

Because the raids are being conducted by Immigration and Customs Enforcement (Ice), a federal agency, local governments can do little to stop Ice agents from knocking on the doors of immigrants and potentially separating families.

But that hasn’t stopped mayors from fighting against Ice and Donald Trump’s anti-immigration policies.

Some cities have set up know-your-rights hotlines and are offering money for legal counsel in the hope that support and resources will limit fear around the raids. Most mayors have said they have directed their local police departments not to cooperate with Ice.

“What we are working on is doing everything we can to push back on everything that the Trump administration is doing,” said Chicago’s mayor, Lori Lightfoot, at a press conference on Thursday. Lightfoot said the city had cut off Ice’s access to the Chicago police department’s database, though other federal agencies may still have access.

In Baltimore, the mayor and police commissioner introduced a police department policy that prohibits officers from helping immigration officials in civil investigations.

Along with support from various not-for-profit organizations, city councils in Chicago, Denver, Atlanta and Baltimore have set aside city funds for immigrant legal assistance. New York City has run its legal defense program for immigrants since 2013.

In a press call, Denver’s mayor, Michael Hancock, expressed frustration that Trump was using immigrants to distract the public from problems in the White House.

“He has used our vulnerable immigrants and refugees who are fearing for their very livelihoods and their families to distract us,” Hancock said. “Immigrants are productive contributors to the economic and social cultural fabric of our community, and when they feel unsafe, that is a problem.”

The support of undocumented immigrants from local officials, in the midst of hostility towards them from the White House, builds on the sanctuary city movement.

Many large cities – which tend to lean Democrat – have designated themselves as a sanctuary cities, adopting policies that terminated cooperation with Ice. The federal agency often turns to local police for information and temporary detention space when targeting undocumented immigrants.

Of the nine cities where the raids will take place, six have designated themselves as sanctuary cities. Although Atlanta, Houston and Miami are not sanctuary cities, in part thanks to state laws that have banned sanctuary city policies, the three cities have historically been reluctant to cooperate with Ice.

“It’s difficult as a leader because we’re all scrambling, mayors across the nation,” the mayor of Atlanta,r Keisha Bottoms, told CNN Friday morning. “How do we address this, how do we reassure our communities when we are dealing with the unknown, an unpredictable president who notifies us via Twitter?”