The Extended Deterrence Policy Committee was officially established at a meeting of senior military officials from the two nations, a senior ministry official said.
"Institutionalizing the committee is meaningful for the alliance because it paves the way for the two governments to draw up countermeasures against North Korea's nuclear threats and weapons of mass destruction," the official told Yonhap.
The committee, led by Deputy Defense Minister Chang Kwang-il and Michael Schiffer, U.S. deputy assistant secretary of defense for Asia and Pacific security affairs, will hold its first meeting Washington in February or March.
"Extended deterrence" means the United States can provide tactical and strategic nuclear weapons, conventional arms and missile defense to South Korea in the event of an attack from North Korea.
The allies also reaffirmed their commitment to respond firmly should North Korea strike the South again following the Nov. 23 shelling of the island of Yeonpyeong.