He was speaking to Yonhap News Agency shortly after attending a historic statue transition ceremony at a USFK base in central Seoul.

The monument of Gen. Walton H. Walker, a figure symbolic of the US participation in the 1950-53 Korean War, will be moved to the USFK's expanded Camp Humphreys base in Pyeongtaek, some 70 kilometers south of Seoul, as part of a broader base relocation project.

Lt. Gen. Thomas S. Vandal, the commanding general of the 8th Army, said the South Korea-US alliance will stay robust despite the base relocation.

"Make no mistake about it. Our alliance 'gachigapsida (Let's go together)' spirit remains ironclad and strong," he said in a speech at the ceremony.

Their reaffirmation of the commitment to the alliance came as the communist North has ratcheted up military threats.

North Korea watchers said the unpredictable regime may soon conduct a nuclear test or launch more ballistic missiles.

There has been no report of such a strategic provocation yet.

The North instead conducted a massive live-fire artillery training exercise in Wonsan near the demilitarized zone, sources said, adding hundreds of heavy guns joined it.

"Our military is keeping a close eye on the North Korean military's activities in the vicinity of Wonsan and maintaining a steadfast combat posture," the South's Joint Chiefs of Staff said.

The allies have, in fact, responded with the reinforcement of their combined combat posture. 

The two sides opened a joint live-fire exercise Tuesday involving their major destroyers near the western sea border between the two Koreas.

In a further display of force, the US has dispatched the USS Michigan, a nuclear-powered submarine, to the peninsula.

The Ohio-class guided-missile submarine SSGN 727 arrived at a Busan port for a "routine visit during a regularly scheduled deployment to the Western Pacific," said US Naval Forces Korea.

"This visit is yet another example of the steadfast ROK and US naval partnership," said Rear Adm. Brad Cooper, commander of the forces. “We (US and ROK navies) work closely with one another every day of the year and this well-deserved port visit is a chance for Michigan sailors to enjoy the wonderful Busan culture that US Navy Korea sailors experience each and every day.”

The US Navy also said its guided-missile submarines provide it with "unprecedented strike and special operation mission capabilities from a stealthy, clandestine platform."

Another major joint naval practice exercise will take place in the East Sea later this week, joined by the USS Carl Vinson aircraft carrier and some other US warships.

The series of joint drills are aimed at demonstrating the allies' resolve to retaliate in case of the North's provocations and their "firm defense posture," the South Korean Navy said in a statement. (Yonhap)