WASHINGTON—President Donald Trump’s administration says it plans to sidestep a court agreement that limited detention for immigrant children.

The Department of Homeland Security announced Thursday it would terminate the agreement, which requires the government to release immigrant children generally after 20 days in detention. It would instead adopt regulations that administration officials say will provide for proper care of minors but allow for changes to deter migrants illegally crossing the U.S.-Mexico border.

The government says it wants to detain families for the length of their immigration court proceedings.

The 1997 case that spawned the agreement will almost certainly land back in court. U.S. District Court Judge Dolly M. Ghee already rejected a request by administration lawyers this year to allow for longer family detention.

Advocates for immigrant families have opposed Trump’s detention policies.