In the latest show of force against North Korea, the US and South Korean navies conducted a joint exercise in the Sea of Japan (or East Sea as referred to by the Republic of Korea) on Monday, 26 September.

The US guided missile destroyer USS Spruance joined Seoul's ships, submarines and planes in waters east of the Korean Peninsula. The Spruance and South Korean missile destroyers that took part in the drill were equipped with the Aegis missile defence system, which is touted by manufacturer Lockheed-Martin as "the world's most advanced combat system".

The Aegis missile defence system is reportedly capable of tracking more than 100 targets at a time. It is also the only naval system capable of intercepting ballistic missiles.

"We work side-by-side with our ROK [Republic of Korea] partners every day; we are by their side today at sea, and we will remain by their side to defend against North Korea's unprovoked acts of aggression," Rear Adm Brad Cooper, commander of US Naval Forces Korea and Task Force 78, said in a statement following Monday's exercise.

Following North Korea's fifth and largest nuclear test a few weeks ago, the US flew its Air Force B-1 bombers over the Osan Air Base, south of the South Korean capital of Seoul. It was seen as a show of force by the allies that had warned the North against any military provocation.

Last week, the show of force was repeated by Seoul and Washington in response to Pyongyang's announcement of the successful test of a rocket engine. The US again flew its B-1 bombers, but for the first time the powerful and combat-tested heavy bombers flew closest to the line separating North and South Korea, a US military source was quoted by CNN.

USS Spruance
US and South Korean navies conducted a joint naval drill on Monday, 26 September, involving missile destroyer USS Spruance (in picture) and South's submarines and ships, in latest show of force against North Korea -File photo Reuters

David Straub, a former State Department Korean affairs director, said the show of force was aimed at conveying the message to North Korea that "the United States won't be intimidated by their pursuit of nuclear weapons, much less the threat to use them". Such displays are also "useful in reassuring the South Korean government and people that the United States has both the capability and the will to deter North Korea", Straub added.

However, Victor Cha, Korea Chair at the Center for Strategic and International Studies in Washington, believes that the US mobilising its military assets into the region is part of a US strategy that is "as predictable as it is ineffective".

"With each missile and nuclear test, Kim Jong-un appears to be gaining confidence and certainty that the world will recognize North Korea as a nuclear state and deal with it on those terms," Cha said during congressional testimony on 14 September.

Andre Gerolymatos, coordinator of the Terrorism, Risk and Security Studies Programme at Simon Fraser University, was of the same opinion. He told CNN that flights and military exercises are "not sufficient to cause alarm" in North Korean leader Kim Jong-un.