Warning of the heightened threat of nuclear war in a “world rife with geopolitical tensions and mistrust,” United Nations Secretary-General António Guterres on Wednesday called upon nuclear nations to join the scores of countries that have adopted a landmark treaty banning atomic weapons.

Addressing the first meeting of state parties to the landmark United Nations Treaty on the Prohibition of Nuclear Weapons (TPNW) in Vienna, Guterres called the world’s thermonuclear arsenals “a deadly reminder of countries’ inability to solve problems through dialogue and collaboration.”

“These weapons offer false promises of security and deterrence—while guaranteeing only destruction, death, and endless brinksmanship,” Guterres said in his video message.

“Let’s eliminate these weapons,” he added, “before they eliminate us.”

Guterres lamented that the “terrifying lessons” of the U.S. atomic bombings of Hiroshima and Nagasaki, Japan—the only nuclear war ever waged—are fading from memory. With nine nations now armed with over 13,000 nuclear weapons, the U.N. chief warned that “the once-unthinkable prospect of nuclear conflict is now back within the realm of possibility.”