HOUSTON (AP) — The American Civil Liberties Union is suing the U.S. government over what it calls the unlawful separation of a Congolese woman and her 7-year-old daughter who sought asylum after crossing the California-Mexico border.

The lawsuit filed Monday alleges that nearly four months after seeking asylum, the woman is being held at a detention center in San Diego while her daughter is being held about 2,000 miles (3,200 kilometers) away in a facility for unaccompanied minor children in Chicago.

Advocates accuse the Trump administration of separately detaining adults and their children more frequently than in years past, including in cases where families are seeking asylum through processes established under U.S. law.

The U.S. Department of Homeland Security declined to comment on the lawsuit.