An imposing US aircraft carrier is set to arrive in the southeastern port city of Busan on Tuesday, officials here said, in yet another show of America's military might against growing North Korean threats.

The nuclear-powered USS Nimitz carrier is slated to dock at ROK Fleet Command in the city, 325 kilometers south of Seoul, after its strike group trained with the South Korean Navy in the international waters south of the southern island of Jeju the previous day.

Its presence here is expected to send a warning to Pyongyang, which has been ratcheting up tensions through missile launches and repeated threats to use nuclear weapons in a contingency, observers said.

The flattop is the flagship of Carrier Strike Group 11, which includes USS Bunker Hill, a Ticonderoga-class guided missile cruiser; and two Arleigh Burke-class destroyers, USS Wayne E. Meyer and USS Decatur. It has brought some 70 combat aircraft, including F/A-18 fighters and E-2 Hawkeye early warning aircraft.

On the eve of its port call in Busan, the North fired what it claimed to be "tactical" ballistic missiles loaded with simulated "nuclear warheads." The launch followed a series of earlier weapons tests, including that of an "underwater nuclear attack drone."

In a press meeting aboard USS Nimitz on Monday, Rear Adm. Christopher Sweeney, the commander of the carrier strike group, highlighted the allies' readiness to deal with North Korean threats, according to a pool report.

"I'm not threatened or worried about North Korea," he said, noting that the United States has "deployable strategic assets at the ready on every day."

Concerns have persisted that the North would continue to engage in provocations on the pretext of responding to the allies' ongoing Warrior Shield field drills, including the Ssangyong (double dragon) amphibious landing exercise that runs through April 3.

Last September, USS Ronald Reagan visited the ROK Fleet for allied drills. (Yonhap)