President Donald Trump on Tuesday suggested he will order military forces to the U.S.-Mexico border to secure it and appeared to shrink his border wall requirement to 800 miles.

“We are going to be guarding our border with our military,” he told reporters alongside leaders of Baltic countries at the White House. “That’s a big step.”

At a joint press conference afterward with the Baltic leaders, Trump said he would be meeting with Defense Secretary James Mattis later Tuesday about the idea.

“We have to have strong borders,” he said.

A section of the United States code prohibits a sitting president from using the military as a police force, and border security is a law enforcement function. The president could have been referring to National Guard troops.