The Pentagon said B-1B bombers from Guam, along with F-15C Eagle fighter escorts from Okinawa, Japan, flew in international airspace over waters east of North Korea on Saturday. Unlike on previous so-called "show of force" missions, the U.S. aircraft were not accompanied by South Korean or Japanese planes.

"While conducted unilaterally, this mission was coordinated with regional allies - namely the Republic of Korea and Japan - and was a strong testament to our ironclad alliance," U.S. Pacific Command spokesman Cmdr. Dave Benham told Fox News, using the official name for South Korea. B-1 bombers are no longer part of the U.S. nuclear force, but they are capable of dropping large numbers of conventional bombs.

U.S. Pacific Command would not be more specific about many years it had been since U.S. bombers and fighters had flown that far north of the DMZ, but Benham noted that this century "encompasses the period North Korea has been testing ballistic missiles and nuclear weapons."

At the United Nations, Ri said that his country's nuclear force is "to all intents and purposes, a war deterrent for putting an end to nuclear threat of the U.S. and for preventing its military invasion, and our ultimate goal is to establish the balance of power with the U.S."

He also said that Trump's depiction of Kim as "Rocket Man" makes "our rocket's visit to the entire U.S. mainland inevitable all the more."