A U.S. expert on Korea says South Korea may have to choose between North Korea and the United States if ongoing efforts to dismantle the North's nuclear program fail in coming months.

Don Oberdorfer is a professor at Johns Hopkins University's Nitze School of Advanced International Studies in Washington. He said if efforts to curb the North's nuclear weapons program are unsuccessful in the coming months, dangers and tensions are likely to grow in and around the Korean Peninsula.

Oberdorfer made the remarks in an interview with Seoul-based Yonhap News Agency on the occasion of the 4th anniversary of the historic inter-Korean summit in 2000.