President Donald Trump explained Thursday why he cut short a negotiation summit with Kim Jong-Un in Vietnam.

“Sometimes you have to walk and this was just one of those times,” Trump said in a press conference with reporters after he abruptly left the summit with the North Koreans.

Trump said that the walkout was “friendly” and that the two leaders shook hands before departing.

“It was about the sanctions … basically, they wanted the sanctions lifted in their entirety, and we couldn’t do that,” the president said.

He explained that the two diplomatic teams were unable to reach an agreement on denuclearization, and felt that it was “inappropriate” to sign an agreement that did not make any sense.

“He wants to de-nuke, but he wants to do some areas that aren’t what we want,” Trump said.

Secretary of State Mike Pompeo said that both sides were “much closer” to a deal than they were 36 hours ago, but that they were unable to reach an agreement.

“You always have to be prepared to walk,” Trump said, noting that if he signed a bad deal it would be difficult to defend.

He admitted that the United States had papers drawn up for some kind of deal, but that it was not good enough.

“I’d much rather do it right than do it fast,” he said.

Trump said that Kim promised not to resume nuclear and missile testing despite the talks ending abruptly.