The U.N.'s nuclear watchdog plans to establish a permanent presence at the Zaporizhzhia plant in Ukraine after conducting a long-awaited initial inspection of the Russian-occupied facility, amid concerns that heavy shelling in the area could lead to a nuclear disaster engulfing most of Europe.

"We are not going anywhere. The IAEA is now there, it is at the plant and it is not moving," International Atomic Energy Agency Director General Rafael Grossi told reporters Thursday after leading a 14-member expert team across the frontline between Ukrainian-held and Russian-occupied territory to reach the site, despite reports of intense military activity in the area. Grossi said a group of U.N. nuclear safety officials will stay behind at the facility — a vital source of energy for Ukraine — to provide an independent assessment of the situation and help reduce the risk of a severe accident.

The six-reactor complex, Europe’s largest nuclear power facility and the 10th largest in the world, has been one of the major hot spots in the more than six months since Russia invaded its neighbor. It was seized by Russian forces in March but is operated by its Ukrainian staff under the watch of armed soldiers.