This is the South Korean military exercise that made North Korea promise to launch a 'sacred war'

South Korea and the US are holding a scheduled large-scale military drill amid heightened tensions in the divided Korean peninsula. On August 4, alleged North Korean mines seriously wounded two South Korean border guards. And on August 20, the Koreas exchanged artillery fire along their de-militarized zone, although no one was reported injured.

Today, North Korea has ordered its front-line troops onto a war footing in a drastic raise in tensions.

This drastic increase in tensions is underlying this year's annual Ulchi Freedom Guardian (UFG), which runs from August 17 to 28 and involves 30,000 US troops alongside 50,000 of their South Korean counterparts. According to a statement from the Combined Forces Command (CFC) in South Korea, the exercise is "a routine and defense-oriented exercise designed to enhance CFC readiness, protect the region and maintain stability on the Korean peninsula."

UFG features a number of exercises meant to improve response to fires, potential terrorist attacks, and the use of chemical or biological weapons in major South Korean cities.

North Korea sees the exercises as a veiled threat of war. The Kim regime has vowed to respond with the "strongest military counteraction" if it the operation is not canceled. In 2012, Kim Jong Un insisted that his troops be ready to engage in a "sacred war" in response to that year's UFG.

Here are some of the best photos of the 2014 and 2015 editions of UFG.