Updated

President Trump's decision to end an Obama-era program shielding illegal immigrants brought to the U.S. as children has left hundreds of military service members facing an uncertain future.

Department of Homeland Security spokesman Dave Lapan told reporters Thursday that "less than 900" people currently in uniform — or who have signed up to serve — are recipients of work authorization through the Deferred Action for Childhood Arrival, or DACA, program.

On Tuesday, Trump ordered an end to DACA in six months, giving Congress time to find a legislative solution.

Lapan admitted that it was "unclear" what would happen to soldiers who have completed basic training or are on active duty should their DACA protection expire.

"That is still being worked out" with the Defense Department, Lapan said.

However, Lapan said that so-called "dreamers" whose DACA protection expires before they complete basic training will have their service contract nullified and they could be subject to deportation proceedings.

Fox News' Jake Gibson and the Associated Press contributed to this report.