'I broke up with you first, I want my ring back,' After Trump-Kim 'breakup', Twitter cracks up over commemorative coins

US President Donald Trump's letter to North Korean leader Kim Jong-un cancelling their summit next month prompted a deluge of derisory comments on Twitter on Thursday, including many about the now discounted commemorative coin pre-minted for the occasion.

The "President Trump United States and Korea Summit" coin was the "deal of the day" at the White House Gift Shop on Thursday after Trump earlier in the day called off the historic summit with Kim, citing Pyongyang's "open hostility."

The coin, which was selling for $19.95 after the price was cut from $24.95,shows gold embossed images of Trump and Kim facing each other with a montage of their countries' flags in the background. Kim's title is designated as "Supreme Leader".

The coin was minted by the US military, which has long issued "challenge coins" commemorating specific events or accomplishments. A military detachment called the White House Communications Agency, regularly issues coins when the president travels abroad.

What some described as the "breakup" tone of Trump's letter to Kim, coupled with the premature coins, drew a lively response from social media users on Twitter.

"I am going to break up with you before you can break up with me and I get to keep all of the commemorative coins... SO THERE," said @AOPhoenix.

"Are they going to make a coin to commemorate the breakup between Kim Jong Un and Trump?" Steelsnowflake1 asked.

"No bel! No bel! Worthless coins! Worthless coins!", said Sally Thomas, @SallyTh24566914, referring to speculation that Trump could be in line for a Nobel Peace Prize if the summit takes place.

"Seeing as Trump never apologises for anything, except the break up letter to Kimmy, do you think he'll keep the money from the commemorative coin?," morosejews asked.

"What about his break up email to Kim Jong? What will he do with all his silly challenge coins he made?," asked Stablegenius Steve @numberone2.

"You didn't break up with me, I broke up with you first. I want my ring back and reimbursed for the stupid coins I had made," said @sandrafualkenb1.

Trump's letter to Kim announced his abrupt withdrawal from what would have been a first-ever meeting between a serving US president and a North Korean leader. It had been due to take place in Singapore on June 12.

"Sadly, based on the tremendous anger and open hostility displayed in your most recent statement, I feel it would be inappropriate, at this time, to have this long-planned meeting," Trump wrote in his letter to Kim.

"Please let this letter serve to represent that the Singapore summit, for the good of both parties, but to the detriment of the world, will not take place."