South Korea's unification minister said Thursday that a flurry of diplomacy to salvage a summit between the United States and North Korea has indicated their leaders' "strong resolve" for their prospective encounter and denuclearization.

Cho Myoung-gyon made the remarks in a speech that a senior ministry official read out on his behalf during an international seminar on regional peace at Tokyo's Keio University.

"It (ongoing diplomacy) is an opportunity for us to reaffirm the strong resolve of the leaders vis-a-vis the denuclearization of the Korean Peninsula and the US-North Korea summit," Cho said in the speech.

"Though there have been twists and turns, things are in progress in a direction towards holding (the summit) as planned," he added.

The summit between US President Donald Trump and North Korean leader Kim Jong-un is expected to be held on June 12 in Singapore.

Last Thursday, Trump canceled it, citing "open hostility" from the North, but he later suggested it would go ahead as planned following Pyongyang's conciliatory gesture.

Currently, US and North Korean officials are holding talks to hash out the agenda, logistics and other details ahead of the summit.

Also in the speech, Cho anticipated that the denuclearization process might not be "smooth."

"A series of events (over the past weeks) were a remainder that denuclearization and the process of establishing peace would not be that smooth," the minister said.

"What matters is that those in the negotiations walk towards one (shared) goal steadfastly as they try to narrow differences through incessant dialogue and expand common ground," he added.

Cho also reiterated that Seoul will maintain close communication and cooperation with Washington, Pyongyang and other countries to ensure that a deal can be struck at the Trump-Kim summit to achieve denuclearization and security assurances for the North.(Yonhap)