Antonio Guterres also said the impact of the conflict could cause a food supply crisis next year. “Simply put, the world will run out of food,” he said. Guterres was speaking at the start of a UN Security Council meeting a day after Vladimir Putin raised the stakes in his invasion of Ukraine, announcing a partial mobilization and threatening to use nuclear weapons “if the territorial integrity of our country is threatened.” Putin also authorized referendums in four Ukrainian regions to pave the way for annexation, raising the prospect that he would then consider Ukrainian businesses to retake them as a threat to Russia’s “territorial integrity”. US President Joe Biden has dismissed the nuclear threat as reckless and supporters of Ukraine have said they will not be deterred from providing military support. “The idea of nuclear conflict, once unthinkable, has become a subject of debate. That in itself is completely unacceptable,” Guterres said. “I am also deeply concerned by reports of plans to hold so-called referendums in areas of Ukraine that are not currently under government control,” he said. “Any annexation of a state’s territory by another state resulting from the threat or use of force is a violation of the UN Charter and international law.” Russia was widely condemned at Thursday’s Security Council meeting chaired by French Foreign Minister Catherine Colonnade. China’s Foreign Minister Wang Yi reiterated Beijing’s line that the UN charter and territorial integrity should be upheld, without directly criticizing Russia, which is an ally. Wang, however, offered Moscow no rhetorical support in a carefully worded speech. The council was briefed by the chief prosecutor of the international criminal court (ICC), Karim Khan, on the investigation of mass graves found in Ukrainian towns liberated from Russian occupation. Hahn said “the echoes of Nuremberg must be heard today,” citing the precedent set by the Nazi war crimes trials. Russian Foreign Minister Sergei Lavrov did not address Guterres’ comment, repeating Moscow’s discredited claims that Ukraine is run by “neo-Nazis” and that the war was caused by the mistreatment of Russian-speakers in the Donbass. He said Russia had no confidence in the ICC. Lavrov was not in the room for the ministers who spoke before him and left as soon as he delivered his own speech. The Russian conscription expansion, originally intended to draft 300,000 soldiers, has sparked protests around Russia and an exodus of military-age men. Putin’s escalation of the war in the face of territorial losses to Ukrainian forces has led to consideration of a new round of sanctions. EU foreign ministers agreed in Brussels to prepare a new package that is expected to include general economic and individual measures. Guterres also pointed to the success of the UN-brokered Black Sea Grains Initiative in exporting more than 4.3 million tonnes of food, which he said has brought down food prices sharply. But he said falling Russian fertilizer and ammonia exports were already creating shortages in West Africa and elsewhere. “If the fertilizer market does not stabilize next year, it could bring the food supply crisis,” he said. In his speech on Wednesday, Biden said that food and fertilizers are not subject to international sanctions. “Let me be absolutely clear about one thing: our sanctions expressly allow – they expressly allow – Russia the ability to export food and fertilizer. No restrictions. It is Russia’s war that is exacerbating food insecurity and only Russia can end it,” he said. Speaking at Thursday’s Security Council meeting, UK Foreign Secretary James Cleverley echoed this and blamed Moscow for the crisis. “Let’s be clear, we don’t sanction food,” he said. “It is Russia’s actions that prevent food and fertilizers from reaching developing countries. It is Russia’s tactics and bombs that are responsible for destroying Ukraine’s agricultural infrastructure and delaying its exports.”