International Atomic Energy Agency head Rafael Grossi said on Thursday that the U.N. nuclear watchdog considered the Zaporizhzhia nuclear power plant to be a Ukrainian facility.
Russia captured the plant in southern Ukraine in March, shortly after invading Ukraine, and Russian President Vladimir Putin ordered his government on Wednesday to take control of it.
The plant is Europe's largest, and Ukrainian staff have continued to operate it.
"This is a matter that has to do with international law ... we want the war to stop immediately, and of course, the position of the IAEA is that this facility is a Ukrainian facility," Grossi told reporters in Kyiv.
He was due to travel to Moscow for talks to meet Russian officials following his talks in the Ukrainian capital.
