But the presidential office remains cautious, saying that holding a three-way summit and declaring an end to the Korean War all depends on the outcome of the North Korea-US summit.

“We plan to make preparations (for a trip) when there is an invitation, though we still do not know whether there will be one,” the official told reporters on the condition of anonymity on Thursday. “We have no plans to prepare for a three-way summit in advance.”

Cheong Wa Dae confirmed Wednesday it had sent an official to Singapore to prepare for Moon’s official visit to the city state in July, but it triggered speculation that Seoul may be preparing for a three-way summit between the two Koreas and the US.

North Korea and the US seem to have reached a broad agreement that North Korea take steps to abandon its nuclear weapons program in a short, compressed period of time in return for the US taking measures to guarantee the Kim Jong-un regime’s survival.

“If Kim Yong-chol and Pompeo confirm the date for the North Korea-US summit, it would mean many things have been adjusted and the summit is likely to be a success. Then, it would be possible and also efficient to hold the trilateral summit among the Koreas and the US to declare an end to the war,” said Hong Min, a senior researcher at the Korea Institute for National Unification. 

“Declaring an end to the war does not take much time and is not difficult technically,” Hong said. “It is a political statement. It is the first step toward building political trust between North Korea and the US.”

Cho Sung-ryul, a senior researcher at the Institute for National Security Strategy, also said that it could be possibly done in Singapore a day after the historic summit. 

“It is one of the measures the US could take to guarantee the North Korean regime’s security until North Korea completes denuclearization and the US ultimately signs a peace treaty with the North,” he said. 

But China could pose a challenge, he added.

“If so, it could complicate Seoul’s plan to declare an end to the war right after the US-North Korea summit,” he said.

China on Thursday signaled its intention to actively engage in the process of ending the war. 

“China is a major party concerned with the Korean Peninsula issues, and will continue to play a suitable role as a signatory to the Armistice Agreement,” Chinese Foreign Ministry Spokeswoman Hua Chunying said in response to a question from Yonhap News Agency.

The presidential office has said that China could be left out of the process of declaring an end to the Korean War, but added its role was essential in signing a peace treaty with the North. China appears to be struggling to retain influence over issues concerning the Korean Peninsula -- key leverage over the US.

Other analysts were more cautious about the possibility of the three-way summit, raising questions over whether the US would agree to it. 

“Even if the North Korea-US summit is held as planned and the talks go well, I don’t think that the US will agree to declare an end to the Korean War immediately in Singapore,” said Park Won-gon, a professor at Handong Global University. “Doing so will likely be a political burden for Trump. The US will see whether the outcome of the summit is well-received before agreeing to declare an end to the Korean War. ”

“Also, Trump wants to be at the center of the spotlight. Given his personality, I don’t think he will allow President Moon to steal the limelight.”

By Ock Hyun-ju (laeticia.ock@heraldcorp.com)

Staff Reporter Yeo Jun-suk contributed to the report -- Ed