Hungarian Prime Minister Péter Magyar on Thursday cast doubt on a deal struck by his predecessor that would see Russia’s state nuclear company Rosatom expand Hungary’s nuclear power capacity.

Weeks of extreme heat and drought have pushed the Danube River to record lows, slashing output at Hungary’s Paks nuclear plant — which normally supplies around a third of the country’s electricity — to little more than 10 percent.

“These plans were accepted despite the fact that nuclear power plants that do not operate with a closed-circuit cooling system and are so exposed to the environment are no longer being built in the world,” said Magyar, per local media.