North Korea conducts drills with mock-up South Korean bunkers

North Korea has been conducting military drills with mock-up targets of South Korean front-line bunkers, a senior military source said Thursday, further raising tensions on the Korean Peninsula following its missile launches. The North Korean Army has conducted infiltration drills under scenarios in which the artillery units strike mock-up military camp sites similar to the South Korean Army's general posts (GPs) and general outposts (GOPs) in the middle of day. "The North Korean military has openly carried out the drills with very specific targets to make surprise attacks or infiltrate into GPs or GOPs," the source said, asking for anonymity. In response to the infiltration drills targeted at front-line troops, South Korean Army troops have stepped up their guard near the border and monitoring of the North Korean military, according to another military official. A GOP is stationed just south of the demilitarized zone (DMZ) as part of a detachment of front-line troops to stand guard against infiltrations or surprise attacks from the enemy. A GP is a small military bunker located inside of the DMZ, tasked with monitoring the North Korean military round the clock. There are about 60 South Korean GPs and 200 North Korean GPs inside of the last Cold War frontier that separates the two Koreas along the 38th parallel since the Korean War ended in 1953 in the Armistice Agreement. Tensions remain high after the communist state test-fired two mid-range ballistic missiles on Wednesday in a calibrated move timed for the trilateral summit between South Korea, the U.S. and Japan, which was held in The Hague on the sidelines of the Nuclear Security Summit. The leaders of the three nations pressured Pyongyang to take concrete steps for denuclearization and vowed to make a unified response to its provocations. The North has test-fired a spate of short-range missiles and rockets from its east coast since late February, in a show of force against the ongoing joint military drills between Seoul and Washington.