Escalating tensions over Ukraine are increasing the risk that nuclear weapons could be used, putting the world in dire jeopardy, the head of the Nobel prize-winning group ICAN told AFP.
"Any conflict involving one or several nuclear-armed states is extremely dangerous," Beatrice Fihn, who leads the International Campaign to Abolish Nuclear Weapons, warned in an interview on Wednesday.
The world's two largest nuclear weapons powers are locked in a stand-off over a Russian troop build-up near the border with Ukraine, amid fears of a looming invasion.
The United States this week rejected Russia's key demand to bar Ukraine from eventual NATO membership, but has offered "reciprocal" measures to address mutual security concerns in a bid to find a "diplomatic path" out of the crisis.
Fihn stressed the urgency of calming the situation, cautioning that in the "very fast-paced security environment... things can escalate very, very quickly."
"I am worried that something will go horribly wrong."
She voiced particular concerns over "nuclear weapons stationed on the border in Russia, but also the ones across Europe", which in the case of a full-scale conflict could become "targets".
"This is the moment when we need to not lean into the war-mongering, macho threats, but really come to the table and negotiate," she said.
Fihn also stressed the need to promote nuclear disarmament in general to help de-escalate the stand-off.
"We've seen voices from Belarus talking about wanting to station Russian nuclear weapons there, which I think is an extremely dangerous situation," she said.
A good way to reduce tensions, she added, would be for Belarus, Ukraine and other countries to sign onto a new global treaty banning the use, development, production, testing, stationing, stockpiling and threat of use of nuclear weapons.
ICAN won the 2017 Nobel Peace Price for its key role in drafting the Treaty on the Prohibition of Nuclear Weapons, which took effect a year ago.
Fifty-nine countries have ratified the treaty, and more have signed it, although none of the states known to possess nuclear weapons are among them.
But Fihn pointed out that Cuba and Venezuela were party to the treaty -- meaning that when Moscow earlier this month hinted it might deploy Russian missiles to those countries, "at least nuclear weapons are off the table".
Signing onto the treaty is "a positive step that countries caught in between" the nuclear powers can take to defuse the situation, she said.
"We would really like to see both Ukraine and Belarus commit to that," she said, adding that "many countries in Europe could do the same to reduce tensions and help the nuclear-armed states get to the table."
Despite the fact that none of the nuclear-armed states are on board, Fihn insisted the treaty was already showing concrete results.
She pointed in particular to how a number of banks and pension funds are pulling out their investments in companies that produce nuclear weapons.
Campaigners expect the treaty eventually to have the same impact as previous international agreements banning landmines and cluster munitions, which have cast stigma on their stockpiling and use, pushing even countries that did not sign to change their behaviour.
But Fihn acknowledged though that this is "not a quick fix", and that it could take years "before you really see a concrete trend".
That is time the world may not have if it cannot avert a full-blown conflict over Ukraine, she warned.
Fihn pointed out that the so-called "Doomsday Clock", representing the judgement of leading science and security experts about perils to human existence, remains at 100 seconds to midnight this year.
This "shows how close we are to the use of nuclear weapons", she said. "It's really a wake-up call."
"I think that this Doomsday Clock is a good reminder that these conflicts, like we see in Ukraine now, can very quickly go wrong.
"Mistakes and miscalculations can happen very quickly."