South Korea and the United States are working to ensure the summit between US President Donald Trump and North Korean leader Kim Jong-un.
South Korean President Mon J-IN and US President Trump Both spoke on Sunday in the telephone.
Kim is scheduled to meet in Singapore on June 12 with the trump.
Kim said on Wednesday that North Korea could not sit for the meeting if United States extra pressure to leave its nuclear weapons.
In this situation South Korea expressed interest in intervening to reduce the gap between the two parties.
Munn's office officials said that on Sunday, Trump and Moon have spoken about 20 minutes on the telephone. Though they did not say anything further.
The statement said, "The two leaders are working very closely and steadily in the upcoming North Korea-USA successful conference on June 12. They also talked about the upcoming South Korean-US upcoming conference. "
Mon will meet with Trump in Washington next Tuesday.
On April 27, the historic meeting left the Korea Peninsula for the failure of the Korean Peninsula, to forget the hostility of two Koreans.
Since then there has been dramatic changes in North Korean behavior. According to the promise, they also started the task of blocking their nuclear weapons test field.
But since last Wednesday, North Korea has started talking about the past.
On the day after threatening to cancel the meeting with Kim Trump, the country's main mediator, Reon Gon, said that they will not negotiate with South Korea until their demands are met.
North Korea has objected to the United States-South Korea joint air trial 'Max Thunder'.
Also, the South Korean government has asked some North Korean Korean restaurant workers to immediately return.
Those restaurant crews visit China from China in 2016. The northern claim has been kidnapped by South Korea.