Pentagon lawyers are reviewing a request by the Department of Homeland Security for the Defense Department to activate 20,000 National Guard troops to enforce immigration laws.

The Department of Homeland Security asked the Pentagon for the troops to secure the border, two U.S. defense officials said, a potential escalation of the Trump administration’s use of the military in its immigration crackdown.

The Department of Homeland Security has asked for more than 20,000 National Guard troops to augment its domestic immigration efforts, multiple outlets reported Thursday.