- The UN secretary-general said nuclear war is "back within the realm of possibility."
- António Guterres made the remarks during a media briefing in New York on Monday.
- Russia put its nuclear deterrent forces on alert following Western sanctions.
UN Secretary-General António Guterres said nuclear war is "back within the realm of possibility" as Russia gave new orders to its nuclear forces as the war on Ukraine drags on.
"Raising the alert of Russian nuclear forces is a bone-chilling development," Guterres said while addressing media on Monday in New York. "The prospect of nuclear conflict, once unthinkable, is now back within the realm of possibility."
He added: "It's time to stop the horror unleashed on the people of Ukraine, and get on the path of diplomacy and peace."
A few days after Russian forces invaded Ukraine in late February, President Vladimir Putin ordered his country's nuclear deterrent forces on high alert. Putin blamed his move on NATO and economic sanctions imposed by Western countries.
Ukrainian President Volodymyr Zelenskyy said last week that Putin's threat to use nuclear weapons is a "bluff."
"The security and safety of nuclear facilities must also be preserved," Guterres said, referring to Russia's control over the Zaporizhzhia nuclear power plant and its push to secure other plants in Ukraine.
Guterres said he's been in contact with a handful of countries in an attempt to mediate the ongoing war such as China, France, Germany, and Israel.
"The appeals for peace must be heard," Guterres said. "It's never too late for diplomacy and dialogue."
As Russia struggles to make gains on the ground in Ukraine, experts have increasingly expressed concern that Putin could potentially take drastic actions — including using nuclear weapons — because he's backed into a corner.
Retired Brig. Gen. Kevin Ryan, a former defense attaché to Russia and senior fellow at Harvard's Belfer Center for Science and International Affairs, recently told Insider he's "very concerned" about Putin's nuclear threats. Putin could use a "small nuclear weapon" to keep NATO and the US out of Ukraine, Ryan said, underscoring that the stakes are extremely high for the Russian leader.
Winning the war in Ukraine is "everything for him now," Ryan said of Putin, adding, "If he doesn't accomplish this, his own people will take him out."
Jonathan Katz, a senior fellow at the German Marshall Fund, earlier this month told Insider that Putin's recent nuclear posturing and threats should be viewed "quite seriously."
"Putin is calculating right now, if this spills over into something more significant he may decide to use whatever weapon is at his disposal," Katz said. "If he feels that this is going beyond Ukraine into these other spaces, including with NATO and the United States, I think all bets are off the table."
This story is developing. Please check back for updates.