North Korea fired artillery towards South Korea for a second time on Wednesday, Yonhap news agency has reported. Earlier in the day, South Korea's military fired artillery towards North Korea in response after artillery shells from the North landed near the disputed sea border. Local residents said that three rounds were fired by the North. South Korea's YTN TV said earlier in the day the incident was provoked by military exercises being held by the North near the volatile Yellow Sea border. The North shelled Yeonpyeong Island last November, killing four people, just months after the alleged North Korean sinking of a South Korean warship. The two Koreas, who technically remain at war following the 1950-53 Korean War, agreed last month to return to six-party talks aimed at ending North Korea's nuclear program.