Russian troops have begun shelling Europe’s largest nuclear power station in Ukraine on Friday, according to a plant official. The Zaporizhzhia plant accounts for about one-quarter of Ukraine’s power generation. The video shows a blast after what appears to be shelling, with smoke rising followed by a fire. The shelling came as fighting intensified at Enerhodar, a city on the Dnieper River. The mayor of Enerhodar said Ukrainian forces were battling Russian troops on the city’s outskirts. The U.N. atomic watchdog agency has expressed grave concern that fighting could cause accidental damage to Ukraine’s 15 nuclear reactors.