SACRAMENTO—Covington & Burling lawyers representing the California legislature are demanding U.S. officials identify any state and local laws that “prohibit or hinder” immigration enforcement, an allegation leveled by Trump administration officials amid an escalation of tension between the Golden State and Washington.

The letter from Covington partner Daniel Shallman to U.S. Attorney General Jeff Sessions and Homeland Security Secretary John Kelly marks the first public foray the law firm has taken since inking a $25,000 monthly contract to represent the state in responding to the Trump administration.