Experts and at least one former US ambassador have cast doubt on Donald Trump’s meeting with Kim Jong-un and the president’s “weird” claim to have rapidly developed a “very special bond” with the dictator.

The historic summit between the pair was described as “theatre” and “a show”, and a former senior general expressed concern that Mr Kim’s profile had been raised significantly without a major concessions on his part.

Gen In-Bum Chun, deputy commander of South Korea’s First Army until 2016 and now a senior adviser to the Korea corporate members of the Association of the US Army, said the “show” put on by Mr Trump was “very exciting”.

But he said he still needed to see detail of North Korea’s intention to commit to “comprehensive, verifiable, irreversible dismantlement” of its nuclear arsenal.

Economic incentives for Pyongyang should come after denuclearisation, he said, but “at the same time, humanitarian activities and humanitarian aid can, I think, be inserted as incentives”.

“There is a very big possibility, as well as a danger, and it might not even be intentional by Kim’s design” that the dictator could emerge from the summit with his reputation strengthened even if he does not stick to any agreement, Gen Chun added in an interview with BBC Radio 4's Today programme before details of the signed document were public.

Michael McFaul, a former US ambassador to Russia, tweeted: “How does one develop a ‘very special bond’ after a few hours of meeting? That’s really weird to me with anyone, but with a North Korean dictator?”

When detail of the document signed by Mr Trump and Mr Kim became known – including that Pyongyang had committed to “work toward complete denuclearisation” of the peninsula – Mr McFaul added: “It means our negotiators achieved nothing new – not one new concession in exchange for legitimation [sic] of North Korean dictator.”

It was a similar commitment to that made by Mr Kim to Moon Jae-in of South Korea in the Panmunjom Declaration earlier this year.

Experts have previously told The Independent that Washington and Pyongyang have very different definitions of “denuclearisation”. One former US State Department official said that, to the North Koreans, it meant “the removal of the threat posed by us, not them” – referring to the thousands of US troops posted in South Korea and the so-called umbrella of other forces in the region.

Singapore Summit: historic first meeting between Trump and Kim Jong-un Show all 20 1 /20 Singapore Summit: historic first meeting between Trump and Kim Jong-un Singapore Summit: historic first meeting between Trump and Kim Jong-un Mr Trump and Mr Kim leave following their historic meeting AFP/Getty Singapore Summit: historic first meeting between Trump and Kim Jong-un Mr Trump and Mr Kim sign a document committing to peace between their nations, amongst other things EPA Singapore Summit: historic first meeting between Trump and Kim Jong-un Mr Trump holds up a document that both he and Mr Kim have signed AFP/Getty Singapore Summit: historic first meeting between Trump and Kim Jong-un The two leaders reach out to shake hands for the first time AP Singapore Summit: historic first meeting between Trump and Kim Jong-un Mr Trump and Mr Kim shake hands as they meet for the first time Reuters Singapore Summit: historic first meeting between Trump and Kim Jong-un Mr Trump and Mr Kim walk off stage, following their historic meeting Reuters Singapore Summit: historic first meeting between Trump and Kim Jong-un Mr Trump and Mr Kim take a stroll after their meeting on June 12 Reuters Singapore Summit: historic first meeting between Trump and Kim Jong-un Mr Trump and Mr Kim interrupt their stroll to talk to the media AP Singapore Summit: historic first meeting between Trump and Kim Jong-un Mr Kim and Mr Trump look out over a balcony at the Capella hotel, where they held their meeting on June 12 Reuters Singapore Summit: historic first meeting between Trump and Kim Jong-un Mr Trump takes questions at the press conference following his meeting with with Mr Kim AP Singapore Summit: historic first meeting between Trump and Kim Jong-un Mr Trump appreciates the crowd in the press conference following his meeting with Mr Kim Getty Singapore Summit: historic first meeting between Trump and Kim Jong-un Mr Trump travels to the Istana ahead of the summit with Kim Jong Un on June 12 Reuters Singapore Summit: historic first meeting between Trump and Kim Jong-un Kim Jong Un travels to the Istana ahead of the summit with President Trump on June 12 Reuters Singapore Summit: historic first meeting between Trump and Kim Jong-un Mr Kim poses for a photo with Singapore's Finance Minister Vivian Balkrishnan and Education Minister Ong Ye Kung ahead of the summit with Mr Trump Twitter/Reuters Singapore Summit: historic first meeting between Trump and Kim Jong-un Mr Trump shakes hands with Singapore Prime Minister Lee Hsien Loong, meeting on Monday June 11 in the Istana, Singapore's presidential palace AP Singapore Summit: historic first meeting between Trump and Kim Jong-un At a working lunch on Monday, Singapore's Prime Minister surprised Mr Trump with a birthday cake, in early celebration of his 72nd birthday later in the week EPA Singapore Summit: historic first meeting between Trump and Kim Jong-un US Secretary of State Mike Pompeo answers questions about the summit at a press briefing in Singapore on Monday, June 11 Getty Singapore Summit: historic first meeting between Trump and Kim Jong-un US President Donald Trump arrives at the Paya Lebar Air Base in Singapore on June 10, two days prior to his summit with North Korean leader Kim Jong Un Reuters Singapore Summit: historic first meeting between Trump and Kim Jong-un Mr Trump and Mr Kim met on Tuesday June 12 in the Capella hotel on the island resort of Sentosa, just off the south coast of Singapore AFP/Getty Singapore Summit: historic first meeting between Trump and Kim Jong-un Mr Trump boards Air Force One following the summit AFP/Getty

John Nilsson-Wright, a Cambridge lecturer and senior fellow at Chatham House, said Mr Kim’s “public confidence enhances a sustained public relations win for a #DPRK press operation that hasn’t put a foot wrong since [the] Pyeongchang Olympics”.

“[It is] what we should expect from the ‘theatre state’,” he added in a tweet. He called the summit “the triumph of style (albeit aspirationally worthy) over substance”.

In the document signed on Tuesday, the US and North Korea also agreed to recover and repatriate the remains of soldiers missing and captured during the Korean War; establish new relations; and “build a lasting and stable peace”.

Mr Trump said the meetings, held on Singapore’s Sentosa Island, went “better than anybody could imagine”.