The presidential office said that the two Koreas are holding working-level discussions on replacing an armistice with a peace treaty and seeking a non-aggression pledge between the United States and North Korea.

A senior presidential official told reporters on Sunday that there is need to discuss ways to resolve the North's security concerns to ensure the success of the Washington-Pyongyang summit.

The official made the comment right after President Moon Jae-in explained the outcome of his second summit with North Korean leader Kim Jong-un on Saturday at the truce village of Panmunjeom.

The official said that working-level discussions are underway between the two Koreas on seeking a non-aggression pledge by Washington and Pyongyang, initiating talks for replacing the armistice with a peace treaty or the three nations declaring a formal end to the Korean War.

The official also said that in his recent summit and telephone talks with President Moon Jae-in, U.S. President Donald Trump mentioned multiple times his intent to begin massive economic cooperation with North Korea if his summit with Kim ends successfully.