Nuclear watchdogs are expressing alarm over safety conditions at the Zaporizhzhia nuclear power plant, which has been under Russian control since early March after a fight that led to a fire near one of the plant’s reactors. It is the largest nuclear power plant in Europe and located in the largest city in southeastern Ukraine still under Ukrainian control. The Ukrainian government accused Russia of launching two missiles that flew over the plant earlier this week, and says Russian missiles have also flown near two other nuclear power plants in the country. Ukrainian energy expert Olexi Pasyuk, deputy director of the group Ecoaction, notes that Russian forces likely already disturbed radioactive materials at the Chernobyl zone, scene of the world’s worst nuclear disaster in 1986. “Zaporizhzhia, where you have reactors in operation and they continue to work now, is a far more dangerous situation,” says Pasyuk.