It comes as tension continues to rise between North Korea - located just 50 miles north of Pyeongchang - and the US.

Moon was speaking during a one-day visit to Pyeongchang.

"We have secured a promise from President Trump to do his utmost to make the Pyeongchang Olympic Games safe, and more strongly, we have been given an assurance that the US will guarantee security during the Pyeongchang Winter Olympics," Moon told US broadcaster NBC, according to a script of the interview released by his Presidential Office Cheong Wa Dae.

Earlier this week, Moon told NBC News that joint military exercises with the US planned in February and March could be postponed if North Korea’s capital Pyongyang halted its nuclear and missile tests before Pyeongchang 2018.

The exercises, held every year, would otherwise be expected to clash with the Olympic Truce, due to last from before the start of the Olympic Games on February 9 until after the end of the Paralympics on March 18.

"First of all, the United Nations has passed a resolution to keep a truce during the Olympic Games, which was jointly proposed by the largest number of countries in history," Moon was reported as saying by the Yonhap news agency. 

"In addition, we and the United States have agreed to closely work together and cooperate to make the Olympic Games safe.

"President Trump too has agreed to send a high-level delegation in case he himself cannot take part, and in China, President Xi Jinping has agreed to seriously consider taking part himself and also send a high-level delegation should he be unable to do so."

Last week, South Korea's Vice-Minister of Foreign Affairs Cho Hyun called on North Korea to participate at Pyeongchang 2018, which he says should be a Games "for peace".

Cho was speaking during a Ministerial Meeting at the United Nations Security Council in New York City.

He also urged North Korea to attend the Games, which are scheduled to conclude on February 25, "to seize the opportunity for dialogue".

Making a rare appearance at the meeting was North Korea's permanent representative to the United Nations, Ja Song-nam.

Yonhap reports that he did not respond to Cho's calls and merely reiterated that North Korea's nuclear weapons were "an inevitable self-defensive measure" to defend itself against "threats" from the US.

Cho also warned that North Korea is "in the final stages of nuclear weaponisation" and that the country will "fundamentally alter the security landscape in the region and beyond" if it has the capability of placing a nuclear warhead on an intercontinental ballistic missile.

The International Olympic Committee has claimed to have been "closely monitoring" the situation and believes that Pyeongchang is currently safe for competition.

It is relying on the success of the Olympic Truce signed last month, despite host nation Russia having invaded the Crimea region of Ukraine during the truce window of the last Winter Olympics in Sochi in 2014.

Earlier this month, the US' Ambassador to the United Nations Nikki Haley backtracked on her comments that it remains an "open question" if athletes from the country will compete at Pyeongchang 2018 by insisting a full delegation will attend the event.