North Korean leader Kim Jong-un arrived in Singapore on Sunday, two days ahead of a historic summit with US President Donald Trump.

"Welcomed Chairman Kim Jong Un, who has just arrived in Singapore," Singapore Foreign Minister Vivian Balakrishnan tweeted along with a photo of him shaking hands with Kim in front of his airplane at Changi airport here.

Later, Kim met Singapore Prime Minister Lee Hsien Loong in the prime minister's office, where the two leaders were seen having a friendly chat, Efe news reported.

Trump is scheduled to arrive in Singapore later on Sunday and go directly to his hotel, according to the White House.

Lee, who is expected to meet Trump on Monday, addressing a press conference before receiving Kim, underlined Singapore's neutral role and hoped that the summit results in security and stability for the region.

The summit between Trump and Kim, scheduled to begin at 9 a.m. on Tuesday (June 12) at the Capella Hotel, will be the first meeting between the sitting leaders of North Korea and the US.

Trump described it as a "one-time shot" at peace and said the two were in "unknown territory". The US hopes the summit will kick-off a process that eventually sees Kim give up nuclear weapons, BBC reported.

The two leaders have had an extraordinary up-and-down relationship over the past 18 months, trading insults and threatening war before abruptly changing tack and moving towards a face-to-face meeting.

Trump's first year in office was marked by bitter exchanges with Kim as North Korea conducted several ballistic missile tests in defiance of international warnings.

The US President vowed to unleash "fire and fury" if Pyongyang kept threatening the US. He also referred to Kim as "little rocket man".

In return, Kim called him "mentally deranged" and a "dotard".

Despite the White House's "maximum pressure" campaign, North Korea remained defiant and carried out its sixth nuclear test in September 2017. Soon after, Kim declared that his country had achieved its mission of becoming a nuclear state, with missiles that could reach the US.

But in early 2018, North Korea began attempts to improve relations with South Korea by sending a team and delegates to the Winter Olympics in Pyeongchang.

In March, Trump surprised the world by accepting an invitation from Kim -- delivered via Seoul -- to meet in person.

Since then, the path to the summit has been rocky, with Trump at one point calling it off completely. But after some diplomatic scrambling, the two leaders will now sit down together.

Singapore is only the third country Kim has visited since he became leader in 2011.

He made his first trip abroad as leader to China in March, and in April he became the first North Korean leader to step foot in South Korea when he met South Korean President Moon Jae-in at Panmunjom on their mutual border.