North Korea could send signals of willingness to re-engage the United States as the communist nation appears to have realized that all of its diplomatic efforts to break out of isolation have failed, a former senior American diplomat said Monday.

Stapleton Roy, who served as ambassador to Beijing, made the remark during a Wilson Center discussion, citing "a prominent former" Chinese official he met when he visited China as a member of the National Committee on American Foreign Policy delegation.

"I did hear from a prominent former official the view that North Korea was coming or had come to the realization that all of its efforts to find a way out of the box that it had put itself in had failed," Roy said of the meeting with the unidentified Chinese official.

"They looked at Europe, they looked at Russia, they looked at elsewhere and no country or a group of countries was prepared to help them out of the problems they had put themselves in," he said.

"And therefore, the suggestion was that we should be alert to look for signals from North Korea that it wanted to re-engage."

Roy, currently a distinguished scholar at the Kissinger Institute, said that the North's recent offer to hold talks with the United States on a peace treaty replacing the Korean War armistice could be one of such signs of willingness for engagement.

That proposal, which the U.S. immediately rejected, urging Pyongyang to focus on the denulearization talks, also shows that the North wants to "marginalize" South Korea to deal only with the United States, Roy said, adding that such an attempt is a "nonstarter."

The former diplomat said that the North Korean nuclear issue did not feature high in his delegation's discussions in China, adding that Beijing appears to be as much frustrated as the United States about "not knowing how to engage with the North Koreans on this issue."

"Every approach that might open the door to a significant discussion on denuclearization has been closed by Kim Jong-un. So they were very frustrated, and therefore there was not a high profile in terms of how we can come to grips with it," he said.

The NCAFP delegation recently traveled not only to China but also to South Korea, Japan and Taiwan. The team included Evans Revere, a former deputy assistant secretary of state; Gerald Curtis, a Columbia University professor; and Michael McDevitt, a senior fellow at the Center for Naval Analyses.

Speaking about Korea-Japan relations, Revere said that what he found in Japan was that the "Korea fatigue," which refers to Japanese frustration with South Korea over history disputes, was "much more intense, much more widespread than I had anticipated."

The mood in Japan was that the country was "more optimistic about Japan's ability to mend relations with Beijing than to improve relations with the ROK. That's a problem for the United States. Reasons I think are obvious," Revere said.

Still, Revere said that the recent summit between South Korean President Park Geun-hye and Japanese Prime Minister Shinzo Abe "as good as we could have expected" in that the meeting could serve as a basis for resolving the issue of Japan's wartime sexual slavery.

"I think perhaps a bit of corner has been turned here in that at least there is a basis for moving forward and resolving the core issue, the comfort women issue," he said.

Curtis said that the scene of "Korea fatigue" in Japan is a "terrible problem."

"I think the need for Japan to be more magnanimous, more forthcoming to find a way, to make a proposal that the Koreans can accept, will accept to move this issue off the center of this relationship is absolutely critical," he said. "But at the moment, I don't see reasons for great optimism." (Yonhap)