South Korea's top diplomat on Thursday called for "extra caution" over implications from recent political developments in North Korea, vowing continued efforts to induce positive changes in the communist neighbor.

North Korea is widely believed to be experiencing a political upheaval including, most notably, the shock execution of its leader Kim Jong-un's once-powerful uncle Jang Song-thaek for treason last month.

"We have to pay extra caution for effects that the North's execution of Jang Song-thaek would have on not only its own regime but also inter-Korean relations, its nuclear issues and relations with neighbors," Foreign Minister Yun Byung-se said in his New Year's message.

"Particularly after Jang's the execution, there have been growing uncertainty and vicissitudes in North Korean politics," Yun said, while emphasizing greater vigilance against Pyongyang's possible provocation.

Stressing the importance of maintaining "a strong deterrence against North Korea based on close international cooperation," the minister called for efforts to "induce changes in North Korea via pressure and persuasion."

As another example of "a wave of unprecedented and complicated diplomatic challenges" that South Korea is confronted with, Yun pointed to how Japan's rightward moves would be developed further.

Japan has drawn international criticism for Prime Minister Shinzo Abe's recent visit to the controversial Yasukuni shrine in Tokyo, which honors war criminals of World War II.

"Japanese politicians' attitude not only caused self-inflicted isolation but put a stumbling block in the way of bilateral relations and peace and cooperation in Northeast Asia," Yun said.

He then emphasized the importance of trilateral cooperation among Seoul, Tokyo and Beijing.

Pointing to strong national security as a precondition to happiness of the people and economic development, Yun urged to strive for deepening diplomatic ties with "key neighboring countries such as the United States, China and Russia" and for expanding the country's diplomatic horizon as a global middle power.

"We've shown our diplomatic possibilities on the global arena rather than being sandwiched by powerful neighbors ... Our efforts for 2014 should be put toward preparing for national reunification and the miracle on the Han River." (Yonhap News)