"Some responsive measures are needed to provide momentum for North Korea's denuclearization," Wi said, adding "Sanctions relief could also be considered in the negotiation process.”

South Korean President Lee Jae Myung said in an earlier interview that Seoul may consider sanctions relief on Pyongyang under a three-stage roadmap of suspension, reduction, and denuclearization of the Korean Peninsula, which he announced last month.

Seoul will approach such a strategy via active efforts for dialogue with Pyongyang, based on the solid alliance with the United States, President Lee said.