WASHINGTON - President Donald Trump rejected on Thursday (April 11) the idea of easing sanctions on North Korea to move denuclearisation talks along, adding that now was not the right time for economic concessions being sought by Seoul, which would allow it to resume joint projects with Pyongyang like the Kaesong industrial complex.

Mr Trump however said he could be open to "various smaller deals" to achieve the denuclearisation of North Korea in a more incremental manner, which would be a departure from his and his administration's all-or-nothing approach so far.

"There are various smaller deals that maybe could happen," said Mr Trump in remarks before his meeting with South Korean President Moon Jae-in, with whom he said he would discuss "certain humanitarian things" for North Korea.

"But at this moment, we're talking about the big deal. The big deal is we have to get rid of the nuclear weapons."

Mr Moon is on a whirlwind 24-hour visit to Washington DC in the hopes of encouraging the United States and North Korea to continue their talks, following the abrupt end of the Hanoi summit between Mr Trump and North Korean leader Kim Jong Un in February.

The complete denuclearisation of North Korea remains the ultimate goal of negotiations, said both presidents, with Mr Moon stressing that South Korea was "absolutely on the same page" as the US on the issue.

Mr Moon, who played a key role in getting both leaders to the negotiating table, said that the Hanoi summit "was not a source of disappointment, but part of a bigger process that will lead to a bigger agreement".

"The important task that I face right now is to maintain the momentum of dialogue," he said through a translator.

Mr Trump said that a third summit between him and Mr Kim - with whom he said he had a "very, very good" relationship - could happen, although he declined to comment on whether he had been in communication with Mr Kim in the last few weeks.

A three-way summit between Mr Trump, Mr Moon and Mr Kim was also possible.

Said Mr Trump: "I think that would be largely dependent on Chairman Kim, because President Moon will do what's necessary."

Mr Trump said that he and Mr Moon would also discuss trade and military issues, including Seoul's purchase of military equipment from the US.

South Korea is a key ally of America in the Asia-Pacific, with some 28,500 American troops stationed on South Korean soil. A recent wrinkle in their relationship - the Trump administration's unhappiness with the portion of the bill Seoul was footing for the American troop presence in South Korea - was temporarily put to rest with the signing of a one-year cost-sharing deal in February.

South Korea is also one of America's key trading partners. Both countries recently re-negotiated their free trade agreement, which will limit Seoul's steel exports to the US but exempt it from the Trump administration's 25 per cent tariffs on steel.

Mr Moon, who arrived in the US on Wednesday evening, also joined Mr Trump for a working lunch with other top US and South Korean officials. He will begin his journey back to Seoul in the evening,

Before his meeting with Mr Trump, Mr Moon also met Secretary of State Mike Pompeo and National Security Adviser John Bolton.

The South Korean President emphasised the importance of maintaining dialogue between the US and North Korea to peacefully resolve the North Korean nuclear issue, and both top officials assured him that the US will continue its dialogue with Pyongyang, said South Korea's Blue House in a statement.

But Mr Trump stressed that denuclearisation of North Korea was a long-term process that would not happen overnight. "It's step-by-step. It's not going to go fast," he said. "If it goes fast, it's not going to be the proper deal."