During severe battle between Russian and Ukrainian forces, a fire broke out in a training building near Europe’s largest nuclear power plant, Ukraine’s official emergency service stated on Friday.

There was no sign of heightened radiation levels at the Zaporizhzhia plant, which generates more than a fifth of Ukraine’s total power, according to US Energy Secretary Jennifer Granholm.

Shelling and smoke rose near a five-story building at the facility site, according to a video feed from the plant verified by Reuters.

A massive candescent ball lighted up the sky, bursting beside a car park and sending smoke pouring across the compound, according to footage filmed at night, which showed one building aflame and a salvo of incoming shells. It was not immediately clear who was in control of the plant.