Secretary-General Antonio Guterres sounded the alarm over the war in Ukraine, nuclear threats in Asia and the Middle East, and other tensions, warning that "humanity is just one misunderstanding, one miscalculation away from nuclear annihilation."
The warning came Monday as a pandemic-delayed conference opened to review the 50-year-old Nuclear Nonproliferation Treaty, which is aimed at preventing the spread of nuclear weapons and eventually achieving a nuclear-free world.
The threat of nuclear catastrophe was also raised by the United States, Japan, Germany, the U.N. Nuclear chief and many other opening speakers.
Russia, which came under criticism from some speakers, didn't give its address in its scheduled slot Monday but was expected to speak Tuesday. China's representative was scheduled to speak Tuesday.
U.S. Secretary of State Antony Blinken said North Korea is preparing to conduct its seventh nuclear test, Iran "has either been unwilling or unable" to accept a deal to return to the 2015 nuclear agreement aimed at reining in its nuclear program, and Russia is "engaged in reckless, dangerous nuclear saber-rattling" in Ukraine. He cited Russian President Vladimir Putin's warning after its Feb. 24 invasion that any attempt to interfere would lead to "consequences you have never seen," emphasising that his country is "one of the most potent nuclear powers."