Three U.S. aircraft carriers were set to join together in an ongoing exercise with the South Korean Navy in the East Sea on Sunday in an unprecedented show of force against a provocative North Korea.
Of the three flattops -- USS Ronald Reagan, USS Nimitz and USS Theodore Roosevelt -- one has already entered the operational area, called the Korea Theater of Operations (KTO), while the others will partake later in the day following drills with Japan, an informed source said.
The KTO refers to an area that the commander of the South Korea-U.S. combined forces is to zone off for military operations in case of a contingency. It could also involve open seas.
It marks the first time for three U.S. aircraft carriers to be deployed for a joint exercise with South Korea, officials said.
Apart from the nuclear-powered aircraft carriers, 11 U.S. Aegis ships and seven South Korean warships, including two Aegis destroyers, were set to participate in the drills.
South Korea's Joint Chiefs of Staff (JCS) said that the maneuvers are aimed at enhancing the credibility of "extended deterrence" against the North's nuclear and missile provocations. Extended deterrence refers to the U.S. commitment to defend its ally by mobilizing all military capabilities, nuclear and conventional, against the North's aggression.
During the drills, the allied navies will show off their readiness to retaliate in the event of a contingency, the JCS said.
"The combined drills underscore the strong might and will of the South Korea-U.S. alliance," a Seoul official said, declining to be named.
The exercise comes after the two countries agreed in their recent defense ministers' talks to expand the rotational deployment of U.S. strategic military assets to the Korean Peninsula to better cope with North Korean provocations.