Trump becomes first sitting US president to set foot inside North Korea 

US President Donald Trump has become the first sitting US president to set foot inside North Korea when he crossed over the demarcation line. 

Trump and North Korean leader Kim Jong-un shook hands in the demilitarised zone (DMZ) that separates North and South Korea.

"It's nice to see you again," Kim reportedly told President Trump. "I never expected to meet you in this place."

About Trump stepping into North Korea, Kim Jong-un told "It's a very courageous and determined act."

Trump thanked Kim, and added that the two of them have "a great friendship".

It was a "great day for the world", Trump said after meeting North Korean leader Kim.

"It's an honour for me to be here," Trump added, as the two men talked with South Korean President Moon Jae-in on Seoul's side of the border.

"We met and liked each other from day one," Trump added.

Kim and Trump also had an informal chat amid the media scrum.

Trump said ''We are hearing from Kim directly''.

“You hear that voice, no one hears this voice, he doesn’t do press conferences,” he said.

Trump said he wants to thank Kim for responding to his Twitter invitation to meet.

“If he didn’t show up the press was going to make me look very bad,” said Trump.

“If you look back two-and-a-half years, before I was president, it was a very very bad situation, a very dangerous situation for North Korea, South Korea, for the world. The relationship we have developed has been so much for so many people,” Trump added.

“Thank you for asking me to step over that line, I didn’t know if you were going to ask me to do that, I thought you might, but I was ready to do that if you asked,” he added.

Trump called the meeting “very historic”.

Earlier Trump arrived Sunday in the DMZ accompanied by South Korean President Moon Jae-in.

An earnest-looking Trump toured an observation post overlooking North Korean territory, with a US military officer pointing out the sights.