The defense chiefs of South Korea and the United States visited a US air base operating nuclear-capable B-1B and B-52 strategic bombers Thursday in a highly choreographed move to highlight America's military might amid evolving North Korean threats.

Defense Minister Lee Jong-sup and his US counterpart, Lloyd Austin, toured the Joint Base Andrews in Prince George's County, Maryland, and were briefed on key features of the bombers and their firepower.

The visit came shortly after they wrapped up their annual Security Consultative Meeting at the Pentagon, where Austin underscored Washington's "ironclad" security commitment to the defense of the South.

The SCM took place in the wake of a series of North Korean missile and artillery launches, including that of an intercontinental ballistic missile Thursday.

At the base, Lee said the visit to the military venue signals that should the North engage in a nuclear provocation, the allies' response would be a "strong" one that is "diametrically different" from the past, according to Seoul's defense ministry.

Lee added that the visit would send a strong warning to the North while delivering a message to the South Korean public about the strengthening of the US' extended deterrence.

Extended deterrence refers to Washington's commitment to mobilizing a full range of its military capabilities, both nuclear and conventional, to defend its ally.

At the base, Maj. Mark Olme pointed out the four-engine B-1B bomber is a "very capable, venerable" asset that can "be anywhere in the world within about 18-24 hours."

There, Lee and Austin also encouraged American troops and stressed the importance of the allies' "watertight" deterrence cooperation against North Korean threats. (Yonhap)