The United States should consider engaging with North Korea multilaterally should its bilateral efforts continue to go ignored by the recalcitrant North, former US envoys to denuclearization talks with the North said Friday.

They also argued a multilateral process must at least involve China, which they said has far more leverage over the North than the United States.

"The fact is we don't have a dialogue (with North Korea)," said Joseph DeTrani, former special envoy for six-nation negotiations with North Korea. "The option is for North Korea to come back and their leader or representative, their special envoy should be meeting with ours ambassadors. That's point No. 1. But if that's not kicking in, China is so important in this equation and we all know this."

"So why not have China, why not ask China, and hopefully China is doing this as we speak, encourage North Korea to come back to the table, to come back and sit down with the United States and talk about complete, verifiable denuclearization?" he said in a webinar, jointly hosted by the Universal Peace Federation and Washington Times Foundation.

Pyongyang has stayed away from denuclearization talks with Washington since leader Kim Jong-un's Hanoi summit with former US President Donald Trump ended without a deal in February 2019.

The Biden administration said it had reached out to the North in February, and again when its extensive North Korea policy review came to an end in April, but that Pyongyang had remained unresponsive.

Sung Kim, US special envoy for North Korea, again reached out to the North this week in Seoul, saying his country is willing to meet with the North "anywhere, anytime without preconditions."

North Korea flatly dismissed the latest US outreach, with leader Kim's sister, Kim Yo-jong, saying in an issued statement that the US hope for dialogue will only face a "greater disappointment."

Christopher Hill, former US ambassador to South Korea and also top US envoy to the six-party talks, said the US should consider reconstituting the multilateral process.

"I don't care if they call it the six parties or whatever, but what I do care about is the idea that the US by itself cannot leverage the end of this problem. We need other countries to be engaged and other countries who have a substantial interest in a positive outcome," he said in the virtual seminar.

The six-party talks, which had also involved South Korea, China, Japan and Russia, ended in 2009 when North Korea quit the process.

Hill highlighted the importance of engaging with US allies, such as South Korea, but also emphasized the need to include China in any multilateral format.

"After all, the North Korean states, to a great extent, it owes its very existence to China. And so, China, I think it is fair to say, has leverage with North Korea. Perhaps they don't have as much leverage as some American observers suggest they do, but they certainly have more leverage than they suggest that they do," he added.

Hill also noted the number of countries involved in the six-party talks was not an arbitrary number.

"It reflected countries that I think have a direct interest," he said. "I think these countries all need to be involved and I think it behooves the US to see if we can work with these countries."

The call for the US to work with China and others comes amid a growing rivalry between Washington and Beijing, but the former US diplomats insisted the countries must cooperate when they can.

"These are issues where we can work with China. China can show an overture to the US and to the world that they are willing to work on not only climate, trade issues, but also issues of national security like North Korea and the nuclear issue," said DeTrani.

Hill argued the US and China working together on an issue of mutual concern such as North Korea may even help improve their bilateral relations.

"Now clearly the US-China relationship, with all its difficulties, I don't think it's just going to be resolved by addressing bilateral problems between that relationship, like a lot of things," Hill said.

"I think our ability to work with China could be enhanced if we can look at a third country situation or another issue out there and see if we can kind of find a way forward cooperating, and that can help improve some of the bilateral (problems)," he added.