Immigration agents in the United States have been directed to track down and deport thousands of migrant children who entered the country without their parents, according to an internal memo obtained by Reuters.

More than 600,000 immigrant children have crossed the U.S.-Mexico border without a parent or legal guardian since 2019, according to government data.

The Friday notice from the United States Department of Interior obtained by The Associated Press does not explain the Trump administration decision to reinstate the program. It states that it “cancels” the order to halt legal services to migrant children. “Acacia Center for Justice may resume all activities,” the short notice says.