Kim Jung-un and North Korea did this last week — i.e. they said they tested their very first hydrogen bomb.
While many believe it was nothing more than a “boosted fission device”, rather than a traditional hydrogen bomb (that utilizes nuclear fusion), it was still — in a likelihood — a high-powered explosive device. And, like a gun in the hands of an angry someone “non compos mentis”, it’s better to be safe than sorry and put your guard up where you can.
And, so, that’s what the commander of the U.N. Command/Combined Forces Command/United States Forces Korea ordered be done.
This from Reuters:
U.S. forces in South Korea were put on their highest level of alert on Monday in case of any provocation from North Korea, following North Korea’s nuclear test last week.
Curtis Scaparrotti, Commander, U.N. Command/Combined Forces Command/United States Forces Korea (USFK), made the order during a visit to the Osan Air Base, operated jointly by the United States and South Korea, a USFK official said.
Here’s footage of a B-52 surrounded by various fighters during a drill at Osan airbase (30 milies south of Seoul) shortly before the announcement by Scaparrotti.
Here’s Lieutenant Terrence O’Shaughnessy of U.S Forces Korea addressing the press not long after the aerial exercise (alongside a South Korean military representative):
It’s also worth noting that South Korea has fired up the loudspeaker announcements into North Korea along the Demilitarized Zone.