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.

President Donald Trump signed an executive order Wednesday to bar undocumented migrants from accessing public benefits, even though they’re already denied most federally funded programs—his latest move to tamp down on illegal immigration, though it wasn’t immediately clear which initiatives would be impacted.

ICE did not say why it had not previously sought to detain Jose Fernando-Perez, who was placed on house arrest in 2022.