Obama is visiting Seoul this week to speak at a forum hosted by South Korea's Chosun Ilbo newspaper, where, earlier on Monday, he said North Korea's pursuit of nuclear weapons had "done nothing to secure the North Korean people."
Moon later briefed Obama on his summit with incumbent US President Donald Trump last week, an aide at South Korea's presidential Blue House, Yoon Young-chan, told a media briefing.
"President Moon said he talked to President Trump about using sanctions and pressure to resolve the North Korean missile and nuclear problem, but also to use dialog at the same time," Yoon said.
"He said it is the last opportunity for North Korea to enter the door of dialog."