In a highly unusual development, North Korea called a post-midnight press briefing in Hanoi to dispute some of the claims made earlier in the day by Donald Trump in a press conference that the US president had held following a summit that ended unexpectedly with no declaration and no agreement.

“What we have asked for was partial lifting of sanctions, not entirely,” Pyongyang’s Foreign Minister Ri Yong Ho said at the late-night briefing, according to Kyodo News. “In detail, we asked to lift five sanctions that were imposed within 2016 and 2017, out of total 11 sanctions, which would affect ordinary people’s economy and life.”

Ri’s statement contradicted what Trump had said hours earlier in his own press conference.

Then, Trump had claimed that the summit had come to an unsuccessful conclusion due to North Korea’s stance. “It was about the sanctions, they basically wanted the sanctions lifted in their entirety,” he said. “We could not do it.”  Explaining his negotiating tactics, Trump said: “Sometimes you have to walk. This was just one of those times.”

Kyodo reported that Ri also said North Korea told the United States that Pyongyang would “eternally” dismantle the country’s central Yongbyon nuclear complex if sanctions were partially lifted, while proposing to Washington a written pledge ending nuclear and ballistic missile tests.

The late-night meeting was held at Hanoi’s Melia Hotel, where the North Korean delegation, including national leader Kim Jong Un and his sister Yo Jong, is staying amid tight security.

It is highly unusual for high-level North Korean officials to give press briefings to foreign reporters, though the country’s delegation to the United Nations in New York occasionally does so.

The unorthodox timing and convening of the press conference reflected events on Thursday morning, when North Korean leader Kim Jong Un had answered two questions from reporters for – it is believed – the first time ever.

The post-midnight timing was atypical, and it is not clear how international and local media were selected and contacted for the briefing – apparently by Vietnamese authorities.

Across Hanoi, groups of journalists who had not been selected for the briefing, and who had been relaxing in coffee shops and bars across the city after the conclusion of the summit, were galvanized. Noting reports of the press conference on mobile devices, they jumped into taxis and raced to the hotel.

But there, in pouring rain, they were halted at a barrier outside the hotel by Vietnamese security officials. Some media carried out on-the-spot TV interviews in front of the barrier.

One North Korean expert who joined soaked journalists outside the hotel suggested that Kim’s delegation were keen to get their message across.

“The fact that they wanted to respond [to Trump’s messaging] is obviously substantive,” said Chris Green of International Crisis Group. “This is certainly about North Korea responding to a situation where the US has the voice.”

The delegation, Green suggested, may have been shaken by the unexpected outcome of the summit.

“It is unusual to conduct an international summit, which is very expensive, and not have something come out of it,” he said.

Kim Jong Un has been surprised, and possibly spooked, by Trump’s brusque negotiating behavior before.

Kim requested, at just 24-hour’s notice, a summit with South Korean President Moon Jae-in on May 26, 2018. The meeting was duly held in the truce village of Panmunjom in the Demilitarized Zone.  It took place after Trump had, on May 24, abruptly canceled his planned summit with Kim in Singapore, citing North Korean hostility.

After the swiftly convened summit with Moon, the Singapore summit got back on track, and took place in June.