The US military is sending the Arleigh Burke-class guided-missile destroyer USS Spruance from its home port of San Diego to operate off the west coast (presumably of Mexico) to "support actions at the southern US border."
Lat week, the Navy sent another guided-missile destroyer, the USS Gravely, into the Gulf of Mexico on a similarly described mission.
Both destroyers will be accompanied by US Coast Guard Law Enforcement Detachments.