The UN nuclear watchdog said Ukraine told it on Saturday that Russia was planning to take full and permanent control of the Zaporizhzhya nuclear power plant, Europe's biggest, but that Russia had later denied this.
"The President of Ukraine's nuclear power plant operator Energoatom, Petro Kotin, said in a letter to the Director General that around 400 Russian soldiers were 'being present full time on site' (at Zaporizhzhya)," the International Atomic Energy Agency (IAEA) added in a statement on its website.
The IAEA said the Ukrainian regulator had also informed it that efforts to repair damaged power lines at the Chernobyl nuclear plant were continuing and that diesel generators were providing backup power to systems relevant for safety.