Donald Trump's lawyer has risked jeopardising the US-North Korea summit with incendiary comments suggesting Kim Jong-un "begged for it" to happen, diplomatic experts have warned.

Rudy Giuliani, the brash former New York City mayor, said at an event in Tel Aviv on Wednesday that, after the meeting between the two world leaders was initially cancelled, "Kim Jong-un got back on his hands and knees and begged for it, which is exactly the position you want to put him in".

There has not yet been an official response to Mr Giuliani's statement from the North Korean side. The last time a senior American official offended Pyongyang - when Vice President Mike Pence said North Korea "may end like Libya" - relations rapidly deteriorated and the 12 June summit was briefly called off.

The meeting, as things stand, is still scheduled to go ahead on Singapore's resort island of Sentosa. Japan's Shinzo Abe flew in to Washington late on Wednesday to hold last-minute talks with Mr Trump in preparation.

But former diplomats say Mr Giuliani's remarks once again put the US-North Korea rapprochement in doubt. Jan Eliasson, the former deputy secretary-general of the UN and foreign minister of Sweden, said the comment "certainly does not improve the prospects for the Singapore meeting". Sweden has a long history of intermediating between Washington and Pyongyang.

Evans JR Revere, a former State Department diplomat and North Korea specialist, was more blunt. “If the North Koreans needed a reason to cancel the meeting, the Americans just gave it to them,” he told the New York Times.

Challenged in an interview later on Wednesday with the Associated Press, Mr Giuliani rejected the suggestion such comments might sour the atmosphere ahead of next week's summit, saying the North Korean leader must understand the US is in a position of strength.

"It is pointing out that the president is the stronger figure," Mr Giuliani said. "And you're not going to have useful negotiations unless he accepts that."

Mr Giuliani said Mr Trump had had no choice but to call off the meeting after the North Koreans insulted Mr Pence, as well as threatening America's "nuclear annihilation".

"President Trump didn't take that. What he did was he called off the summit," he said.

Mr Giuliani said Kim Jong-un quickly changed his position after that point, expressed willingness to discuss denuclearisation and asked to have the meeting again.

"That's what I mean by begging for it," Mr Giuliani said.

Mr Giuliani, who serves as Mr Trump's lawyer in the Russian investigation, did concede that he was sharing a personal opinion and that he is not part of the US foreign policy team.

Meanwhile, Mr Abe was stopping off in Washington to see Mr Trump before the pair make their way to the G-7 summit in Canada.

The two have struck up a close relationship since even before Mr Trump was inaugurated last year. Mr Abe was the first world premier to hold talks with the president-elect declaring as early as 16 November 2016 that Mr Trump was a "trustworthy leader" for America.

Korea Summit: Kim Jong-un crosses border for historic meeting Show all 25 1 /25 Korea Summit: Kim Jong-un crosses border for historic meeting Korea Summit: Kim Jong-un crosses border for historic meeting North Korean leader Kim Jong-un and South Korean President Moon Jae-in raise their hands after signing on a joint statement Korea Summit Press Pool via AP Korea Summit: Kim Jong-un crosses border for historic meeting Kim Jong-un heads towards Moon Jae-in to shake his hand between the military demarcation line, at the Joint Security Area on the Demilitarized Zone in the border village of Panmunjom in Paju EPA Korea Summit: Kim Jong-un crosses border for historic meeting South Korean President Moon Jae-in and North Korean leader Kim Jong-un hold hands as they cross the military demarcation line EPA Korea Summit: Kim Jong-un crosses border for historic meeting South Koreans react while watching a screen reporting the Inter Korean Summit Getty Korea Summit: Kim Jong-un crosses border for historic meeting South Korean President Moon Jae-in and North Korean leader Kim Jong-un chat as they arrive at the Peace House Reuters Korea Summit: Kim Jong-un crosses border for historic meeting North Korea’s leader Kim Jong-un was escorted by bodyguards from the North to the Military Demarcation Line that divides the two Koreas to meet with his South Korean counterpart at the truce village AFP/Getty Korea Summit: Kim Jong-un crosses border for historic meeting North Korean leader Kim Jong-un crosses the military demarcation line to meet with South Korean President Moon Jae-in AP Korea Summit: Kim Jong-un crosses border for historic meeting Kim Jong-un and Moon Jae-in shake hands Getty Korea Summit: Kim Jong-un crosses border for historic meeting North Korean leader Kim Jong-un and South Korean President Moon Jae-in shake hands after Kim crossing the military demarcation line Getty Korea Summit: Kim Jong-un crosses border for historic meeting South Korean President Moon Jae-in and North Korean leader Kim Jong-un at the Joint Security Area EPA Korea Summit: Kim Jong-un crosses border for historic meeting South Korean President Moon Jae-in and North Korean leader Kim Jong-Un speak with two South Korean children who presented Kim Jong-un with a bouquet of flowers EPA Korea Summit: Kim Jong-un crosses border for historic meeting Moon Jae-in Kim Jong-un pose for photographers at the Joint Security Area (JSA) EPA Korea Summit: Kim Jong-un crosses border for historic meeting North Korean leader Kim Jong-un signs the guest book as South Korean President Moon Jae-in looks on Getty Images Korea Summit: Kim Jong-un crosses border for historic meeting North Korean leader Kim Jong-un’s entry in the guestbook. The writing reads ‘A new history starts now. An age of peace, from the starting point of history’ Korea Summit Press Pool/Pool via Reuters Korea Summit: Kim Jong-un crosses border for historic meeting South Korean President Moon Jae-In and North Korean leader Kim Jong-un talk during their summit meeting at the Peace House EPA Korea Summit: Kim Jong-un crosses border for historic meeting North Korea's leader Kim Jong-un smiles AFP/Getty Korea Summit: Kim Jong-un crosses border for historic meeting North Korean leader Kim Jong-un poses with South Korean President Moon Jae-in for a photo inside the Peace House AP Korea Summit: Kim Jong-un crosses border for historic meeting North Korea’s leader Kim Jong-un talks with South Korea’s President Moon Jae-in AFP/Getty Korea Summit: Kim Jong-un crosses border for historic meeting North Korean leader Kim Jong-un and South Korean President Moon Jae-in prepare to plant a pine tree near the military demarcation line AP Korea Summit: Kim Jong-un crosses border for historic meeting South Korean President Moon Jae-in and North Korean leader Kim Jong-un applaud after planting a tree at the truce village Korea Summit Press Pool/Pool via Reuters Korea Summit: Kim Jong-un crosses border for historic meeting North Korea’s leader Kim Jong-un and South Korea’s President Moon Jae-in take a walk after they planted a tree AFP/Getty Korea Summit: Kim Jong-un crosses border for historic meeting North Korea’s leader Kim Jong-un talks with South Korea’s President Moon Jae-in at a bench on a bridge next to the military demarcation line at the truce village of Panmunjom AFP/Getty Korea Summit: Kim Jong-un crosses border for historic meeting North Korean leader Kim Jong-un and South Korean President Moon Jae-in sign on a joint statement Korea Broadcasting System via AP Korea Summit: Kim Jong-un crosses border for historic meeting North Korean leader Kim Jong-un and South Korean President Moon Jae-in embrace each other after signing on a joint statement Korea Summit Press Pool via AP Korea Summit: Kim Jong-un crosses border for historic meeting North Korean leader Kim Jong-un, left, and South Korean President Moon Jae-in shake hands after their joint announcement AP

According to Japan's state broadcaster, the pair will hold their seventh meeting at the White House on Thursday. Mr Abe wants to confirm close cooperation in information-sharing and other areas before the Singapore summit, NHK reported.

The Japanese prime minister also wants assurances that Mr Trump and Mr Kim will work towards ending the nuclear threat posed by North Korea to Japanese territories.