The U.S. Air Force says it launched two Guam-based B-1B bombers Thursday, accompanied by fighter jets from South Korea and Japan, in an exercise in the area of the Korean peninsula.
North Korean state news agency KCNA on Friday reacted harshly to the drills, calling them a "surprise nuclear strike drill."
"The reality clearly shows that the gangster-like U.S. imperialists are ... aggravating the situation of the Korean peninsula and seeking to ignite a nuclear war," KCNA said.
While the exercise came a day before President Donald Trump was scheduled to leave on a 12-day trip to Japan, South Korea, China, Vietnam and the Philippines, the Air Force said the bombers' flight was not a response to "any current event."
In a statement, the Air Force said the exercise was planned in advance and that the aircraft have since returned "to their respective home stations."
The last time the U.S. military flew such a mission was October 10, when Trump met with top defense officials to discuss how to respond to any threat from North Korea.
Trump and North Korean leader Kim Jong Un have carried on a war of words via public statements since Trump took office in January. North Korea has said it is working on a nuclear-tipped missile that is capable of hitting the U.S. mainland.