WASHINGTON -- US and North Korean officials will meet again on the inter-Korean border after a one-day break Monday, a diplomatic source said, as they continue preparations for a potential summit between their leaders.

The two sides met Sunday (Korea time) on the northern side of the border, with the US delegation led by Amb. Sung Kim and the North Korean delegation led by Vice Foreign Minister Choe Son-hui.

These teams are reportedly responsible for agreeing on the substance of any summit between US President Donald Trump and North Korean leader Kim Jong-un, which was originally planned for June 12 in Singapore but canceled by the American president last week.

Trump has since said the summit could still be held on the same date.

"The two sides held their first working-level meeting Sunday and then took a break without meeting again on Monday," the source told Yonhap on condition of anonymity. "I believe they plan to meet again as early as Tuesday and no later than Wednesday."

The one-day break was intended as a sort of "breather" after both sides laid out their ideas for what a denuclearization deal would look like, the source said, adding that the next session will likely delve into the details.

"It's not because they've hit a snag in negotiations," he said.

The US wants to see complete, verifiable and irreversible dismantlement of North Korea's nuclear weapons program, including by transferring nuclear warheads out of the country. But Pyongyang has rejected "unilateral" denuclearization and called for a "phased and synchronous" process that would likely involve sanctions relief in exchange for dismantlement steps.

The two sides have also been arranging separate meetings in Singapore to discuss logistical issues for the potential summit.(Yonhap)