The U.S. Justice Department has given California election officials 48 hours to review a federal list of people it alleges may be undocumented immigrants registered to vote, threatening to seek emergency court relief if the state misses the deadline. Acting Deputy Attorney General Trent McCotter sent letters Tuesday to California Secretary of State Shirley Weber and Los Angeles County Registrar-Recorder Dean Logan. The letters said the department had provided a thumb drive containing the names and directed officials to act by Thursday. McCotter also asked California to set aside and refrain from counting ballots already returned by listed voters whose citizenship could not be verified, according to the letters. The federal claim does not, by itself, establish that anyone on the list is a noncitizen or cast an unlawful ballot. “If you cannot implement this process by then, given the ongoing federal election, the United States will have no choice but to seek emergency relief,” McCotter wrote. Logan said Thursday that his office was reviewing the information with the California secretary of state and attorney general. He said the county had not accessed the drive because doing so would conflict with established data-privacy and information-security procedures. The dispute puts election officials under pressure to respond to a federal demand during the November midterm election period, while also following their security protocols. The letters threaten litigation but do not establish that any ballots have been improperly cast or counted.