Russia has rejected a call by the United Nations to create a demilitarized zone around the Russian-controlled Zaporizhzhia Nuclear Power Station as fighting threatens Europe’s largest nuclear plant. Russia’s Foreign Ministry on Thursday called the Russian army’s occupation of the site in southeastern Ukraine a guarantee against a “Chernobyl scenario” — a reference to the 1986 nuclear catastrophe in northern Ukraine. Russia’s rejection of the deal follows Thursday’s visit by U.N. Secretary-General António Guterres to Lviv, in western Ukraine, where he met with Ukrainian President Volodymyr Zelensky and Turkish President Recep Tayyip Erdogan. Guterres said fighting by Russia and Ukraine near the plant risked a worldwide nuclear disaster.

Secretary-General António Guterres: “Military equipment and personnel should be withdrawn from the plant. Further deployment of forces or equipment to the site must be avoided. The area needs to be demilitarized. And we must tell it as it is: Any potential damage to Zaporizhzhia is suicide.”

Today Guterres is visiting the coastal city of Odessa to inspect grain shipments, after a U.N.- and Turkey-brokered deal guaranteed safe passage to Ukrainian ships in the Black Sea.