Defense Secretary Jim Mattis said the Pentagon will not stand down as lawmakers in Washington scramble to come to an agreement to end a fledgling partial government shutdown over an impasse on a spending measure.

In a memo to agency employees, Mattis explained his high expectations for the military during an event that will constrain the U.S. armed forces.

“We will continue to execute daily operations around the world – ships and submarines will remain at sea, our aircraft will continue to fly and our warfighters will continue to pursue terrorists throughout the Middle East, Africa and South Asia,” Mattis said. “While training for reservists must be curtailed, active forces will stay at their posts adapting their training to achieve the least negative impact on our readiness to fight."

While the shutdown will halt paychecks for troops, cause furloughs for civilian Defense Department workers, and cause disruption for the military, Mattis pledged his "personal commitment that the department’s leadership will do our best to mitigate the impacts of the disruptions and any financial burdens to you and your families."

“Steady as she goes – hold the line. I know our nation can count on you," Mattis said, adding, “Stay alert" just before his signature.

Letter from Secretary Mattis to our great military on #SchumerShutdown

"Steady as she goes - hold the line. I know our Nation can count on you." pic.twitter.com/BvNYQsuAGU — Sarah Sanders (@PressSec) January 20, 2018



The shutdown, which began at midnight, came after Mattis on Friday unveiled a new National Defense Strategy, a major rewrite of strategy that would see a shift away from terrorism as the top U.S. security concern.

"If you don't get the resources ... then your strategy is nothing more than a hallucination, because, without the resources, there's just so much brave young men and women can do," Mattis said at an event in Washington, D.C.

Sen. John McCain, chairman of the Armed Services Committee, warned that such a plan would be “meaningless” unless Congress can pass a longterm budget.