The meeting between US President Donald Trump and DPRK op leader Kim Jong-un in Singapore on Tuesday will start a diplomatic process to try to resolve a standoff over Pyongyang's pursuit of nuclear weapons. Here is a look back at how the road to the summit unfolded.

Jan 1: Kim calls for improved relations and engagement with the Republic of Korea, but adds that he has a nuclear button on his desk. Trump tweets back that he has a bigger and more powerful nuclear button, adding "and my Button works!"

Jan 9: DPRK and ROK officials meet at a border village and agree on the DPRK sending athletes and delegates to the Winter Olympics in the South. Hundreds of North Koreans go to the Pyeongchang Games in February, including Kim's sister.

March 9: ROK envoys meet Trump in Washington and deliver an invitation from Kim to meet; Trump accepts.

March 27: Kim makes surprise trip to Beijing to meet with President Xi Jinping.

April 18: Trump confirms that Mike Pompeo, then CIA chief, had met Kim secretly in the DPRK and said "a good relationship was formed".

April 21: The DPRK says it has suspended nuclear tests and plans to close its test site to focus on its economy.

April 27: Kim meets with ROK President Moon Jae-in.

May 7: Kim meets Xi again in China and calls for stronger cooperation.

May 9: The DPRK releases three Americans who had been imprisoned.

May 10: Trump announces he will meet with Kim in Singapore on June 12.

May 16: The DPRK abruptly cancels a high-level meeting with the South and threatens to cancel the summit with Trump in protest over US-ROK military exercises and American comments that the DPRK should follow the "Libya model" of denuclearization by eliminating everything upfront.

May 22: Trump and Moon meet at the White House, and the ROK president says the "fate and the future of the Korean Peninsula hinge" on the meeting in Singapore.

May 24: The DPRK dismantles its nuclear testing ground, but Trump announces that he's pulling out of the summit, citing the DPRK's "tremendous anger and open hostility".

May 25: The DPRK says it is still willing to hold talks with the US "at any time, (in) any format".

May 26: Kim and Moon meet in a border village in a bid to revive the summit with Trump.

May 30: Envoy Kim Yong-chol, the most senior DPRK official to visit the US in 18 years, arrives in New York for summit prep with Pompeo.

June 1: After meeting Kim Yong-chol at the White House, Trump says his meeting with Kim Jong-un is back on for June 12.

- AP