The United States was very active in its attempts to convince North Korea to resume failed negotiations on denuclearisation, said South Korean presidential security office chief Chung Eui-Yong on Sunday.
"Although it was hard to predict the timing of the new talks between Pyongyang and Washington, the US actively sought to convince North Korea to return to the negotiating table," Sputnik quoted Chung as saying while citing a local media.
Adding that the US side is persuading North Korea very aggressively, the head of national security said, "The third summit could be held and the real progress would be achieved only if the parties started working together."
Further, Chung said, "The South Korean Government was serious about its northern neighbour's words on the deadline for submitting a new decision before the end of the year, therefore Seoul maintained close cooperation with the United States on this issue."
North Korea and the US held talks in October for the first time since Pyongyang and Washington agreed in June to reopen denuclearisation negotiations. However, North Korea walked away, saying the US failed to show flexibility.
North Korean officials on October 27 warned the United States that Pyongyang will only wait till the end of the year before coming up with what they called "a courageous decision".
Kim Yong Chol, vice chairman of the NK's Workers' Party, said that it would be a mistake for Washington to ignore the year-end deadline provided to further the nuclear negotiations process.
North Korea has repeatedly insisted that the removal of penalties will help spur economic growth, while the US has reaffirmed that sanctions will not be removed until the communist country completely stops its nuclear weapons programme.
( With inputs from ANI )