President Donald Trump is “seriously considering” killing the Deferred Action for Childhood Arrivals (DACA) program, according to multiple reports. The exact timing remains uncertain, though immigration advocates are treating a decision as potentially imminent, perhaps as early as Friday.

DACA has since 2012 extended legal status and work permits to more than 800,000 immigrants who were brought to the United States as children. Ending the program would make this population, known as the DREAMers, vulnerable to deportation.

The Department of Homeland Security—which currently has no secretary at the helm and no one nominated to fill the post—announced Thursday that is “reviewing” the status of the DACA program as Texas and nearly a dozen other Republican-controlled states threaten to sue the administration over its legality.

During his bid for president and since taking office, Trump has been all over the map on DACA. He vowed last year to kill the program on his first day in office, but not only did that not happen, his administration has granted and renewed tens of thousands of work permits for DACA-eligible immigrants.

“We’re going to show great heart,” he pledged in February, calling the DACA recipients “absolutely incredible kids.”

But spurred by a virulent immigration hardliner attorney general and several White House aides with nationalist views, the president may soon decide to strip these “incredible kids” of their legal status and work permits.