U.N. Secretary-General Ban Ki-moon says he will work to establish dialogue channels with North Korea's leadership.

In his end-of-year “state of the world” news conference, Ban said Friday that the U.N. sought to establish communication channels with the North Korean government through multilateral efforts, including sending a special envoy to the communist state and having U.N. officials meet with North Korean Foreign Ministry officials at the U.N. He said, however, that efforts to communicate with the North’s leadership have proven difficult.

Ban added that the North’s artillery attack against Yeonpyeong was the largest attack on South Korean territory and people since the Korean War and urged the North to immediately cease its provocations.

Ban said that as a South Korean national he is increasingly and deeply concerned about rising tensions on the Korean Peninsula.