In what appeared to be a not-too-subtle warning to North Korea, the United States military announced today that two nuclear-capable B-2 bombers flew on a 6,500-mile nonstop mission from Missouri to South Korea, dropping dummy munitions on an island bombing range there and immediately returning home without refueling.

The U.S. Strategic Command said the trip was intended to show how the U.S. can conduct long-range strikes quickly. Known as a stealth bomber and resembling some sleek futuristic gizmo out of a Batman movie, the B-2 is designed to fly undetected by Soviet-era radar. But the message was clearly meant for North Korea, whose leaders have been issuing increasingly bombastic threats that it would turn South Korea into a “sea of fire.”

“The B-2 is designed to penetrate Soviet airspace and if necessary could penetrate North Korea at a time of war,” Bruce Klingner, a senior research fellow for Northeast Asia at The Heritage Foundation and a former Korea branch chief for the CIA, told USA Today. “Given North Korea’s increasing threats against South Korea and the United States, including threats of nuclear annihilation, this is meant to deter and send a message that the United States is prepared to respond if things get hot.”

Klinger also said the U.S. is signaling to South Korea that it intends to fulfill its treaty obligations to defend it if necessary.

“The United States is steadfast in its alliance commitment to the defense of the Republic of Korea, to deterring aggression, and to ensuring peace and stability in the region,” stated United States Forces Korea, which oversees all U.S. forces based in South Korea.

The impressive B-2 bomber flight came just days after North Korea issued a statement claiming its missile and artillery units are now on “the highest alert” and prepared to strike South Korea, the U.S. mainland and Hawaii and Guam.

It seems that almost weekly now that the regime of North Korean President Kim Jong Un sends out a barrage of apocalyptic threats against the U.S. and South Korea for provocations real and imagined.

A few days ago, the North claimed the incitement was a U.S. B-52 bomber that flew over South Korea as part of regularly scheduled drills conducted this month.

North Korea said in a statement through its Korean Central News Agency that its strategic rocket and long-range artillery units “are assigned to strike bases of the U.S. imperialist aggressor troops in the U.S. mainland and on Hawaii and Guam and other operational zones in the Pacific, as well as all the enemy targets in South Korea and its vicinity.”

“They should be mindful that everything will be reduced to ashes and flames the moment the first attack is unleashed,” the North Korean command said in the statement.

This threat came just hours after South Korean President Park Geun-hye warned the North Korean leaders that they risk their very survival if they don’t abandon the nuclear weapons, long-range missiles, provocations and threats.

“I strongly urge North Korea to change,” Park said in a nationally televised speech marking the anniversary of the deaths of 46 sailors, who were killed in 2010 when a North Korean torpedo sank a South Korean navy corvette. “North Korea must immediately abandon its thought that nuclear weapons will protect its regime.” This latest volley of threats came after the U.N. Security Council imposed more sanctions on North Korea, after it launched a three-stage rocket in December and third nuclear test last month. Last week Kim visited his country’s military units and inspected live-fire artillery and amphibious landing exercises. He ordered his soldiers to send the enemies “to the bottom of the sea as they run wild like wolves threatened with fire,” according to North Korean media.

Analysts expect North Korea to issue another threatening reaction to the B-2 bomber flight — chest thumping that sometimes resembles middle schoolers on the playground.