A Hwasong-17 intercontinental ballistic missile is raised on a launcher in this photo released by the Korean Central News Agency (KCNA), Saturday, a day after the test-firing. Yonhap

By Kang Seung-woo

North Korea has continued to increase pressure on the United States, with the reclusive state successfully test-firing the most powerful intercontinental ballistic missile (ICBM) in its arsenal, living up to a threat made by its foreign minister, who warned of fiercer military responses.

In addition, its leader has revealed for the first time that his country runs military units in charge of ICBMs, in an apparent move to show that its long-range missile technologies and deployment capability have reached a significant level. The latest revelation heightens the U.S. government's concerns as Washington faces limitations in dealing with new threats from the North while juggling challenges posed by the Ukraine-Russia war and fierce economic competition with China.

According to South Korea's military, a Hwasong-17 ICBM, launched at a lofted angle, traveled some 1,000 kilometers at an altitude of 6,100 kilometers, reaching a top speed of Mach 22, a specification that Japanese Defense Minister Yasukazu Hamada believes could reach the U.S. mainland if launched on a normal trajectory.

"As North Korea successfully tested its Hwasong-17 ICBM on a lofted trajectory, it can conduct a nuclear test or launch the missile at a normal angle in order to further pressure the U.S., while showing off its ICBM capabilities," said Shin Jong-woo, a senior researcher at the Korea Defense and Security Forum.

Although many believe that North Korea has not secured technologies to enable its ICBMs to carry multiple warheads and conduct assisted reentry into the atmosphere, its gradual progress in the development of ICBMs is drawing attention from the U.S.

"Every single time they launch, they learn, and that's concerning," John Kirby, the NSC coordinator for strategic communications, said in a press briefing, Friday (local time).

"Even if the launch is a failure or only partially successful, they still learn, their program still grows and it gets to improve, and, of course, that's destabilizing not just to the (Korean) peninsula but to the region itself."

Making the U.S.' situation worse, North Korea is scheduled to celebrate the fifth anniversary of the successful launch of the Hwasong-15, believed to be theoretically capable of hitting targets anywhere on the U.S. mainland.

"Although it is not clear if North Korea will opt for another ICBM launch with a range capability allowing it to strike anywhere in the U.S., Washington would be unhappy with it and feel pressure," Shin said.

In addition, North Korean leader Kim Jong-un unprecedentedly unveiled the operations of its ICBM units.

According to the state-run Korean Central News Agency, Kim ordered the development of strategic weapons and more intensive training for the ICBM and tactical nuclear weapons units in order to flawlessly take on their important strategic duty in any situation and at any moment.

However, the South Korean Joint Chiefs of Staff said, Monday, it did not have any information on the ICBM units.

Amid mounting threats from North Korea, the U.S. has little room to handle them, according to diplomatic observers.

"There are no available options for the U.S. to deal with the North Korean challenges because tough sanctions on the country have already been put in place," Shin said.

When a trilateral summit between South Korea, the U.S. and Japan took place on the sidelines of the ASEAN summit in Cambodia, last week, they agreed to urge China to play a role in pressuring Pyongyang to give up its nuclear ambitions.

"That's why the U.S. urges China to do something to resolve the North Korea nuclear issue," Shin added.