The prospect of nuclear conflict, once unthinkable, is now back within the realm of possibility,” United Nations Secretary-General António Guterres said. He also called for the security of nuclear facilities in Ukraine, some of which have been attacked by Russian forces. Guterres said that he has been in “close contact” with several countries, including China, France, Germany, India, Israel and Turkey, to discuss mediation efforts to bring an end to the war.