(Reuters) - Donald Trump and North Korean leader Kim Jong Un traded insults and threats during his first presidency over Pyongyang's weapons programs, although they met three times and Trump once quipped "we fell in love" after exchanging letters.
But even with the three summits they held, Trump failed to persuade Kim to give up his nuclear weapons, while diplomatic efforts under the Biden administration also stalled with the North ignoring a call to meet "anywhere, anytime without preconditions".
The relationship is likely to come under fresh focus as Trump returns to the White House and North Korea takes unprecedented steps to help Russia in the Ukraine war.
The following timeline details some key moments in the testy ties between Trump and Kim.
* 2017
Aug. 8 - Trump warns North Korea could face "fire and fury" after Pyongyang test fires intercontinental ballistic missiles (ICBMs).
Sept. 3 - North Korea carries out its sixth nuclear test, claiming to have mastered hydrogen bomb technology.
Sept. 19 - Trump threatens to "totally destroy" North Korea.
Sept. 21 - Kim calls Trump a "mentally deranged U.S. dotard".
Nov. 29 - North Korea test-fires Hwasong-15 ICBM, capable of reaching the entire United States, and declares it has become a nuclear power.
* 2018
Feb. 25 - Kim's envoy expresses willingness for U.S. talks while visiting South Korea for the Winter Olympics. March 8 - South Korean official delivers Kim's invitation for Trump to visit North Korea; Trump agrees to meet Kim.
June 12 - Trump, Kim hold first summit in Singapore, agreeing to de-nuclearisation of the Korean peninsula in exchange for U.S. security guarantees.
June 19 - South Korea, U.S. announce suspension of joint military exercises. Sept. 10 - White House unveils Kim's proposal for second summit.
Sept. 30 - Trump declares at a rally with supporters that "we fell in love" after exchanging letters with Kim.
* 2019
Jan. 1 - Kim says he's ready to meet Trump but warns of taking new path.
Feb. 28 - Second summit between Trump, Kim in Vietnam collapses over conflicting demands by Pyongyang for sanctions relief and by Washington for North Korea to abandon nuclear weapons.
March 22 - Trump says on Twitter, now known as X, that he had "ordered the withdrawal" of "additional large-scale sanctions" against the North, sparking confusion over which ones he is referring to.
April 12 - Kim sets a year-end deadline for the United States to present a new approach to the nuclear talks in a speech to the Supreme People's Assembly.
May 4 - North Korea conducts its first missile test since the November 2017 ICBM launch, firing a new short-range ballistic missile (SRBM) and more.
May 10 - Trump says he did not consider the North's latest missile tests "breach of trust," calling it "standard stuff".
June 11 - Trump says he received a "beautiful letter" from Kim.June 23 - North Korea's state media says Kim received a personal letter from Trump and would "seriously contemplate the interesting content."
June 30 - Trump and Kim meet for the third time at the Demilitarized Zone on the Korean peninsula.
July 16 - North Korea's foreign ministry accuses the United States of putting the nuclear talks at risk with a plan to hold military exercises with South Korea.
Aug. 2 - North Korea fires two more KN-23 SRBMs; Trump says the tests do not violate his agreement with Kim.
Aug. 6, 10, 16, 24 - North Korea fires more KN-23 and tactical missiles and Kim oversees the test of a new "super-large" multiple launch rocket system (MLRS).
Dec. 4 - Trump says he still has confidence in Kim, but notes he "likes sending rockets up, doesn't he?".
* 2020
Jan. 1 - Kim vows to further develop nuclear programs and introduce a "new strategic weapon".
March 3, 9, 14 - North Korea tests MLRS and SRBMs.
March 21 - Kim supervises test of new tactical guided weapon; Trump sends letter to Kim offering help on COVID-19.
Oct. 3 - Kim sends a get-well message to Trump who tested positive for COVID-19.
Oct. 10 - North Korea unveils a new ICBM and SLBM at military parade.
Oct. 22 - Trump says he has a very good relationship with Kim and stopped war; then U.S. Presidential challenger Joe Biden likens Kim to Nazi Germany's Adolf Hitler and calls him a "thug".
* 2022
March 24 - North Korea conducts a full test of an ICBM, the first such launch since 2017.
* 2024
Oct. 30 - North Korea conducts what appeared to be its longest ever ICBM test, which analysts say could be aimed at exerting influence on the U.S. presidential election.