New York's Mayor Bill de Blasio and Los Angeles's Eric Garcetti led a group of twenty-eight mayors in filing a legal brief in support of President Obama's executive actions on immigration, against a lawsuit by 25 states.

In November President Obama used his executive powers to establish new procedures and guidelines for the Departments of Homeland Security, Justice and Labor that allow some undocumented young adults as well as undocumented parents of U.S. citizens and legal permanent residents to remain in the country and work legally and focus federal resources on the deportation of felons instead of families. Obama said he acted after comprehensive immigration reform languished in Congress the previous summer.

But Republicans have called Obama's actions unconstitutional. The lawsuit, led by Texas, argues that the "unilateral suspension of the Nation's immigration laws is unlawful."

The mayors made the announcement at the U.S. Conference of Mayors, which took place in Washington D.C. "Delaying implementation of the President's executive action will further hurt our families, negatively impact our economies, and create unnecessary insecurity in our communities," de Blasio said in a statement.

Earlier this month a dozen states and the District of Columbia filed a brief backing Obama's actions on immigration, asserting his actions are legal and will have a positive impact. The states in that brief were California, Connecticut, Hawaii, Illinois, Iowa, Maryland, Massachusetts, New Mexico, New York, Oregon, Vermont and Washington, along with the District of Columbia.

The mayors argue that Obama's executive actions serve the public interest and ask that the policies be allowed to move forward despite the lawsuit.