South Korean President Moon Jae In said Thursday that denuclearization talks between North Korea and the United States seem to be on right track, according to his press secretary.

"There are mixed evaluations about ongoing negotiations between them, but I see them as on right track and detailed working-level talks seem to have started for sure," Moon was quoted as telling Singapore Prime Minister Lee Hsien Loong in city-state that hosted last month's historic North Korea-U.S. summit.

(South Korean Pres. Moon Jae In, left, and Singapore PM Lee Hsien Loong)

The press secretary, Yoon Young Chan, said Moon also told Lee that the negotiations could achieve success if North Korea commits to complete denuclearization and the international community works together to guarantee that country's security.

About North Korea's criticism over the outcome of U.S. Secretary of State Mike Pompeo's recent visit to Pyongyang, in which it blasted Washington's "unilateral and gangster-like demand for denuclearization," Moon said that is likely just part of Pyongyang's negotiation strategy as it seeks reciprocal movement from Washington.

In an interview with the Straits Times newspaper, published Thursday, Moon stressed that tensions between the United States and North Korea have persisted for nearby 70 years, since the 1950-1953 Korean War, and "cannot be resolved in just one stroke."

He told the Singapore daily said the Korean Peninsula is now "witnessing a great historic transition," but while both Koreas and the United States have jointly taken initial steps, what matters most is devising concrete plans to put into practice the agreements made among leaders.

"The North needs to flesh out its implementation plans for denuclearization, while South Korea and the United States have to swiftly carry out corresponding comprehensive measures. To this end trust is of paramount importance," he said.

Moon is making a three-day state visit to Singapore that ends Friday, after having traveled to India.

Also Thursday, U.S. officials visited the truce village of Panmunjeom, which straddles the border between North and South Korea, for a meeting on repatriation of the remains of U.S. soldiers who died north of the border during the Korean War, but it was canceled after North Korean officials failed to show up.

A South Korean Unification Ministry official said those talks could possibly take place tomorrow.

During the June 12 summit between North Korean Leader Kim Jong Un and U.S. President Donald Trump, the two sides committed to recovering the remains of U.S. soldiers, including the immediate repatriation of those already identified.