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.

Affected organizations said the move would prevent them from offering critical legal services to migrant children who crossed the U.S. southern border without their parents or legal guardians.

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.