Seoul: South Korean and US forces kicked off their joint annual war game on Monday despite strong a backlash from North Korea.
Operation Ulchi Freedom Guardian (UFG) will run till September 2, Xinhua news agency quoted Combined Forces Command as saying.
The computer-assisted simulation exercise will mobilise about 25,000 US troops, including 2,500 reinforcements from the US mainland and the US Pacific Command, while some 50,000 forces from South Korean will join the military exercise.
The combined forces will apply Operation Plan 5015 (Oplan) to this year`s UFG exercise.
The Oplan 5015 is a wartime joint defence scenario signed in June last year between Seoul and Washington to preemptively destroy the Pyonyang`s nuclear and missile bases in times of military conflicts.
All military communications lines between Seoul and Pyongyang have been shut after North Korea`s nuclear detonation in January and its launch of long-range rocket in February which was seen as a disguised test of ballistic missile technology.
North Korea slammed the UFG exercises, saying that the drill was "an outrageous provocation for a nuclear war against the North aimed to encroach upon the dignity and sovereignty of the country and infringe on the vital rights of its people".
Seoul`s unification ministry spokesman Jeong Joon-hee said it was very regrettable for North Korea to distort and denounce the "annually-held defensive" exercise, urging Pyongyang to make a right choice by stopping nuclear and missile developments and avoiding provocative acts.