STORY: U.N. nuclear inspectors arrived in Ukraine's Zaporizhzhia on Wednesday.
They said their mission at the nuclear plant was to prevent an accident and try to stabilize the situation after weeks of shelling nearby.
They are likely to spend the night in the city before visiting the plant, which is on territory controlled by Russia, on Thursday.
Russian-installed officials in the area near the power station suggested the visit might last only one day, but IAEA chief Rafael Grossi says it would last longer.
“The mission will take a few days. If we are able to establish a permanent presence or a continued presence, better said, then it is going to be prolonged. But this first segment, so to speak, is going to take a few days.”
Russia captured the plant, Europe's largest, in early March - and a Russian military force has been there ever since.
But the facility - which supplied Ukraine with 20 percent of its electricity needs before the invasion - is still run by Ukrainian workers.
For weeks now, Russia and Ukraine have accused each other of endangering the plant's safety with shelling - and risking a Chornobyl-style radiation disaster.
Moscow has said radiation levels at the plant are normal - and that it has no intentions of withdrawing its forces for now.