Chicago is asking a federal judge to block President Donald Trump's administration from following through on its threat to withhold public safety grants to so-called sanctuary cities.

Attorneys for the city will be in court Monday to argue their case. Mayor Rahm Emanuel has said Chicago won't "be blackmailed" into changing its values as a city welcoming of immigrants.

Trump's policy stands to withhold public safety grants unless cities agree to tougher enforcement of immigrations laws. Chicago is among several cities refusing to cooperate.

Chicago sued the U.S. Department of Justice last month, arguing the new federal requirements are unconstitutional.

U.S. Attorney General Jeff Sessions has warned that Chicago would forfeit its rights to the federal funds if it insists on violating the "rule of law."