North Korea has reinforced coastal artillery gun positions near its base close to the tense Yellow Sea border, Seoul\'s Yonhap News Agency reported Friday.Yonhap qouted a military official as saying that about 20 new artillery positions have been set up along the shores of Kangryong Country in Hwanghae Province, near the North\'s Kaemori base. Kaemori was the location from where North Korea fired artillery shots at South Korea\'s Yeonpyeong Island in November last year, killing two civilians and two Marines. \"These coastal guns have a range of 12 kilometers and a 76.2-millimeter caliber, and they\'re pointing at Yeonpyeong Island,\" the official was quoted as saying. The base in Kaemori lies about 12 to 13 kilometers from Yeonpyeong. The official also said North Korea has been fortifying its existing gun positions, likely in response to South Korea\'s own movements to bolster its artillery bases. \"Our forces have augmented our defense of islands in the Yellow Sea, and it appears as though North Korea is also making preparations,\" the official said.