The week-long exercise included part of the US troops based here, 5,000 US soldiers from abroad and South Korean military contingents, as well as a US aircraft carrier backed by cruisers and destroyers.

The annual exercise, called RSOI/FE 04, focuses on a mock battle aimed at evaluating command capabilities to receive US forces from abroad.

Hundreds of thousands of South Korean troops are mobilized every year for anti-commando operations and computer war games but South Korea refused to disclose the number of soldiers taking part in this year's drills.

US authorities also maintained low-key publicity on the exercise due to a strong backlash from North Korea, which has reacted nervously to any US-South Korea joint drills amid the impasse over its nuclear weapons programs.

In an angry commentary Sunday, the North's goverment newspaper Minju Josun described the exercise as a "dangerous saber-rattling row to round off war preparations for a preemptive attack" on North Korea.

"It is the temperament of the army and the people of the DPRK (North Korea) to retaliate against provocation and return fire for fire," it warned.

US authorities say the exercise is purely defensive and designed to improve the ability of allied forces to defend South Korea against external aggression.

The 1950-53 Korean War ended in a fragile armistice and the Korean peninsula remains the world's last Cold War frontier with nearly two million troops ready for combat either side of the tense frontier.

The exercise comes as South Korea and the United States are locked in talks on the relocation of some 37,000 US troops stationed here under a mutual defense pact.

The realignment includes a plan to relocate a 15,000-member US infantry division from the frontline with North Korea to bases south of Seoul.

The presence of US troops in South Korean has been a source of anti-American protests, while conservative groups have opposed any changes to long-standing security ties with the United States.

US troops are seen as deterring North Korea's 1.1 million strong army, and their departure would make Seoul, which is just 50 kilometers (30 miles) from the border with North Korea, more vulnerable to artillery attacks.

WAR.WIRE