Updated

President Donald Trump's meeting Thursday with South Korean President Moon Jae-in comes amid uncertainty over whether the leader of North Korea is considering backing out of nuclear negotiations or restarting nuclear and missile tests.

It is Moon's first meeting with Trump since his unsuccessful summit with Kim Jong Un in Hanoi. The South Korean leader, who wants to see a denuclearized Korean Peninsula, has been shuttling between Washington and Pyongyang to resolve the nuclear standoff. Moon has worked aggressively to foster better relations between the North and South and doesn't want to see nuclear talks derailed.

Trump walked away from making a deal with Kim at their meeting in late February. Trump said Kim was asking for sanctions relief without wanting to fully dismantle all of his nuclear weapons programs. North Korean experts are debating whether harsh sanctions can pressure Kim to denuclearize or if they will keep him from the negotiating table.

A senior administration official said Thursday that the U.S. and the international community have "clearly defined the scope" of North Korea's weapons of mass destruction and ballistic missile programs, have a shared understanding of what final, fully verified denuclearization entails and what meaningful progress toward that goal looks like. The official, who spoke on condition of anonymity to discuss the sensitive negotiations, said the North Korean position, so far, has fallen short of that understanding.

Clues about Kim's current stance could be revealed Thursday in the North Korean capital when he is expected to address his country's Supreme People's Assembly. The assembly, the country's version of a parliament without power, is expected to convene to formally approve Kim's latest economic policies and possibly endorse a shift in U.S. strategy following his failed summit with Trump in Hanoi.

North Korea's Deputy Foreign Minister Choe Son Hui said last month that Kim would soon make clear his post-Hanoi position. She said her country might pull out of the nuclear negotiations with the United States, citing a lack corresponding steps to some disarmament measures North Korea took last year. She also hinted Kim was considering whether to continue the talks and his moratorium on nuclear and missile tests.

The Korean Central News Agency on Thursday said that at a party meeting on Wednesday, Kim stressed "self-reliance" in his country to "deal a telling blow to the hostile forces" that "go with bloodshot eyes miscalculating that sanctions can bring" North Korea "to its knees."