"A deliberate threat by North Korea cannot be dismissed entirely," Viatcheslav Kantor, president of the Luxembourg Forum, an NGO whose declared mission is to “prevent nuclear catastrophe”, told an audience of high-level diplomats on Monday.
The forum's 10th anniversary came against a backdrop of renewed concerns about the potential for nuclear war.
In the United States last weekend Republican Senator Bob Corker accused President Donald Trump of trying to start world war three in his ongoing row with North Korea.
"The situation on the Korean peninsula is at a critical level, with constant aggravations due to the North Korean president's [Kim Jong-un] nuclear and missile provocations," said Kantor.
Kim was expected to stage another missile test on Tuesday 10 October as his country marked Party Foundation Day, the anniversary of the creation of the country's ruling party, which is also its only legal one.
Nuclear non-proliferation treaty threatened
Russian lawmaker Anton Morozov, who recently visited the country said Pyongyang had provided calculations suggesting it could now hit the US west coast.
"Time is running out," former Russian foreign affairs minister Igor Ivanov warned the meeting.
His comments come as more nuclear states are ramping up their capability, threatening, he reckons, the validity of the 1968 nuclear weapons non-proliferation treaty.
"In the worst case scenario, a chain reaction could occur in which nuclear proliferation leads to expansion of the nuclear club from nine to 15 or more members by the year 2035," he said.
For Britain's former Prime Minister Tony Blair, the proliferation of nuclear weapons capability is "the most serious threat to the future of humankind".
That future would see a proliferation of regional conflicts and more terrorists gaining access to nuclear explosive devices, Ivanov insisted.
Worse than the Cold War
“Today’s world is much more dangerous than a relatively stable bipolar Cold War architecture," the Russian former minister said. "Those days the rise of China, the nuclear India and Pakistan were unthinkable, not to mention the current madness of the North Korea nuclear regime.”
Times have changed. For the worse, thinks former US Defence Secretary William Perry. He lived through the threat of nuclear war, even being woken up in the night by a false alarm about an imminent attack from the Soviet Union and thinks the threat remains Russia.
"Given the present mistrust and hostility, I'm especially concerned about Russian actions in the nuclear field," he said. "Putin has dropped Russia's policy of a no first use of nuclear weapons and suggested that nukes could be the weapon of choice if Russia feels threatened. He's put rebuilding the Cold War nuclear arsenal as his highest priority. And of course the United States is following suit."
Blair defends Iran nuclear deal
So how can the arms race be controlled?
Through cooperation, saids Blair. "Without China and Russia in alignment with the USA and Europe, it is hard to see how non-proliferation can be successful."
Blair, who today is chairman of the Institute for Global Change, also distanced himself from Trump's criticism of the 2010 Iran nuclear deal, a deal described by the US president in a tweet as "horrendous", blaming it on Senator Bob Corker, who had criticised his line on the question.
“We can debate the wisdom of the deal and some of its terms but now it has been done," Blair argued. "It has a process of verification; it means for now at least that the nuclear programme of Iran can be stalled and the sensible thing, in my opinion, is to preserve it.”
Despite his controversial decision to commit Britain to the 2003 invasion of Iraq on the basis of nuclear arms that proved non-existent, the former prime minister opposed using military action in North Korea, saying it was premature.
Worse case scenario
Perry for his part also thought that military action could backfire and provoke Pyongyang to use its nuclear weapons against neighbouring South Korea and Japan, sparking a regional nuclear war.
He also warned of the danger of nuclear confrontation between India and Pakistan. In his closing statement, Perry played a video of what that scenario would look like, before ending on a note of optimism.
"On balance I think we can work this out without a conflict," he said. "But I think we are taking unnecessary risks of blundering into a nuclear war and that is the risk with an existential consequence."