Trump would not say in an Oval Office interview that he had talked to Kim, but he told the Wall Street Journal, 'I probably have a very good relationship with Kim Jong Un'. "I'm a very flexible person".
"I think the premise of your question is completely ridiculous and shows the lack of knowledge that you have on this process", Sanders retorted, adding that the president's tweet "wasn't confusing to me".
The White House and the Pentagon did not immediately respond to requests for comment.
Technically, South Korea and the United States remain at war with North Korea after the Korean War ended in 1953 with an armistice instead of a peace treaty.
Trump did not give a clear answer on whether he had already spoken with Kim - something that either elusive or deemed inconceivable in previous administrations: "I don't want to comment on it". In December, the Russian Foreign Minister Sergey Lavrov said North Korea wants to engage in a direct dialog with the United States to assure its security, adding that Russia could help with these talks.
Trump spoke Wednesday with South Korean President Moon Jae-in, and the Blue House readout of the call said the USA president promised he wouldn't attack North Korea while the two Asian nations hold talks.
In November, Trump said while on a trip to Vietnam that becoming friends with Kim "might be a unusual thing to happen but it's a possibility".
Trump's strategy with North Korea has been hot and cold.
North Koreans are also genuinely anxious the United States could launch a preventive war on the peninsula. I'm not saying I have or haven't.
Last summer, Mr Trump threatened North Korea with "fire and fury like the world has never seen" in an exchange of taunts with the North, which claimed it was examining plans to launch missiles towards the American territory of Guam. The president said this may happen if all participants in this process, including North Koreans, will be sure that their security can be guaranteed without nuclear weapons. "He is already an absolutely shrewd and mature politician".
"It just was", Jackson said, before asking how people can trust administration officials to relay the president's positions if he changes them seemingly on a whim.
During the talks held on January 9, the two sides agreed on the participation of North Korean athletes in the South Korean Olympics.
Kim has warned the United States that he intends to build a nuclear arsenal capable of hitting the United States, prompting threats of military action by Washington. "A lot of good energy", Trump said at the news conference.