KYIV, Ukraine (AP) — Authorities began distributing iodine tablets to residents near Ukraine’s Zaporizhzhia nuclear power plant Friday in case of a radiation leak, amid mounting fears that the fighting around the complex could trigger a catastrophe.

The move came a day after the plant was temporarily knocked offline because of what officials said was fire damage to a transmission line. The incident heightened dread of a nuclear disaster in a country still haunted by the 1986 explosion at Chernobyl.

Continued shelling was reported in the area overnight, and satellite images from Planet Labs showed fires burning around the complex — Europe’s biggest nuclear plant — over the last several days.

Iodine tablets, which help block the absorption of radioactive iodine by the thyroid gland in a nuclear accident, were issued in the Ukrainian-controlled city of Zaporizhzhia, about 45 kilometers (27 miles) from the plant. A woman and her small daughter were among those receiving the pills.

The UN’s atomic energy agency has been trying to send a team in to inspect and help secure the plant. Officials said preparations for the trip were underway, but it remained unclear when it might take place.

The Zaporizhzhia plant has been occupied by Russian forces and run by Ukrainian workers since the early days of the 6-month-old war. The two sides have repeatedly accused each other of shelling the site.

In Thursday’s incident, Ukraine and Russia blamed one another for the transmission-line damage that knocked the plant off the power grid.

Exactly what went wrong was not clear, but Ukrainian President Volodymr Zelenskyy said the plant’s emergency backup diesel generators had to be activated to supply electricity to operate the complex.

The plant requires power to run the reactors’ vital cooling systems. A loss of cooling could lead to a nuclear meltdown.