The U.S. Department of Defense said on Thursday that South Korea and the United States will reduce the scope of a combined air exercise later this month.

U.S. Rear Admiral William Byrne, vice director of the Joint Staff, said at a press briefing that he's not going to talk specific force numbers, but the upcoming exercise will be reduced in scope from the former Vigilant Ace exercises.

Byrne added the exercise, however, meets all the requirements of the U.S. and South Korean air forces to ensure readiness. 

He stressed that the most important thing to the U.S. in the Korean theater is maintaining readiness and being ready to "fight tonight." 

Byrne said the allies canceled Vigilant Ace a year ago based on the environment on the peninsula at the time, describing this year's iteration of drills as a "combined flying event."

He added that U.S. Forces Korea Commander Robert Abrams and his South Korean counterpart are charged with ensuring that the allies are conducting the right number and type of combined events in order to maintain readiness while allowing diplomats "the space in the room" to continue negotiations with North Korea.