South Korea still hopes to declare an official end to the Korean War before the year's end, an official from the presidential office Cheong Wa Dae said Monday, amid an apparent stumbling block in denuclearization talks between the United States and North Korea.

"Have we not said the goal was to declare an end of the war before the year's end?" Cheong Wa Dae spokesman Kim Eui-kyeom said when asked if there has been any changes to the goal.

He, however, noted the move requires the participation of both Washington and Pyongyang.

"It cannot be done only by a decision of our government or that of the South and the North, and will be possible when all three parties -- the South, the North and the US -- agree, so we are still holding discussions to realize the ultimate goal," he told a daily press briefing.

South Korea and the North technically remain at war as the 1950-53 Korean War ended only with an armistice.

Talks between the US and North Korea have stalled after US President Donald Trump called off a scheduled Pyongyang trip by his top diplomat, Secretary of State Mike Pompeo, in August.

Trump has agreed to resume the talks and also hold his second bilateral summit with North Korean leader Kim Jong-un.

Earlier news reports suggested Pompeo may meet his North Korean counterpart, Kim Yong-chol, as early as this week.

The Cheong Wa Dae spokesman said his government was not aware of any specific dates for the US-North Korea dialogue. The second Trump-Kim summit is not expected to be held at least until January.

The spokesman said the North Korean leader may still visit South Korea before he holds his second meeting with the US president.

Kim's trip to Seoul, if made, will reciprocate Moon's visit to Pyongyang in September for his third bilateral summit with the North Korean leader.

"We are discussing Chairman Kim Jong-un's reciprocal visit before the year's end with all possibilities on the table," he said.

"We are facing a moment when we need to decide whether (Kim's Seoul visit) will be better before or after the second North Korea-US summit, which will be more effective in bringing peace and prosperity to the Korean Peninsula," the spokesman added.

Cheong Wa Dae officials have said Moon will likely hold a bilateral summit with President Trump this week in Argentina where the leaders will attend the annual Group of 20 summit.

The Moon-Trump meeting, if held, will mark the second of its kind since Moon returned home from his trip to Pyongyang in September. (Yonhap)