SEOUL, The success of the historic U.S.-North Korea summit will likely be determined by the leaders' face-to-face meeting rather than by prior working-level negotiations, an official from Seoul's presidential office Cheong Wa Dae said Monday.

"It appears the upcoming summit will be determined by the final negotiation between the two leaders when they meet face to face and hold frank dialogue, rather than a meeting where working-level officials arrange everything and the leaders only ink the agreement as a formal ritual," Cheong Wa Dae spokesman Kim Eui-kyeom said in a press briefing.

U.S. Amb. to the Philippines Sung Kim and North Korea's vice foreign minister Choe Son-hui held last-minute negotiations in Singapore ahead of Tuesday's summit between U.S. President Donald Trump and North Korean leader Kim Jong-un.

Kim noted Cheong Wa Dae had hoped for a three-way summit between Trump, Kim and South Korean President Moon Jae-in but that such a hope has been dashed, ruling out the possibility of a trip by Moon to the Southeast Asian nation.

"It was a U.S.-North Korea summit from the beginning. We had only been bracing for a possible trip (by President Moon) just in case it became a three-way summit during the course of working-level negotiations between the U.S. and North Korea," the spokesman said.

"The current situation shows that things have not gone down that road," he added.

The Trump-Kim summit follows two inter-Korean summits between Moon and Kim, held April 27 and May 26, in which the leaders of the divided Koreas agreed to push for a formal end to the 1950-53 Korean War.

Seoul officials earlier said the Singapore summit, if also attended by Moon, could provide a venue to declare an official end to the Korean War.

Source: Yonhap News Agency