The Pentagon demonstrated what experts are calling an “unprecedented” show of force against North Korea on Sunday, sending B-1B bombers and F-15C fighter escorts to farthest point north of the border between North and South Korea in the 21st century.

“This mission is a demonstration of U.S. resolve and a clear message that the president has many military options to defeat any threat,” Defense Department spokesman Dana White said in a statement.

“North Korea’s weapons program is a grave threat to the Asia-Pacific region and the entire international community. We are prepared to use the full range of military capabilities to defend the U.S. homeland and our allies,” White said.

What also made the mission noteworthy is that it was flown at night and without any allied aircraft from South Korea or Japan. Also, all planes belonged to the U.S. Air Force; there were no Marine Corps F-35B aircraft accompanying the flight.

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