Bulgaria will become the latest European country to reduce its nuclear power output on Friday due to a record drought scorching the continent, the energy ministry said.

The state-owned Kozloduy plant, which supplies more than a third of the country's electricity, relies on the waters of the Danube River for cooling. The facility's two reactors each have a capacity of 1,000 megawatts.

Due to an "unprecedented and critical" drop in Danube water levels, the plant will reduce the capacity of one of its reactors by about 120 megawatts, the ministry said in a statement on Thursday.

The reduction in output is intended to "ensure the safe operation" of the plant, the ministry said, adding that forecasts for the river upstream of Bulgaria "continue to show a downward trend."

It will be the first time power at the plant has been reduced due to "extreme weather and hydrological conditions" since it began operating 52 years ago, according to the ministry.

Romania and Hungary have also recently reduced their nuclear power output due to low Danube levels.

Romania on August 13 completely shut down the Cernavoda plant, which usually generates a fifth of its electricity.

Hungary has meanwhile been scrambling to avoid a complete shutdown of its Paks plant, which has drastically reduced output since late July.

Works to keep the plant operational have included building a riverbed sill and partially submerging two barges loaded with rocks to raise water levels.

Hungary's Prime Minister Peter Magyar on Thursday said the plant would start bringing turbines back online on Sunday and is expected to return to full power generation next week.

Elsewhere in Europe, the Beznau nuclear plant in northern Switzerland was shut down in June due to high river temperatures, while France has also reduced output at several reactors due to the heatwave.

The drought in Europe has been exacerbated by human-induced climate change, according to experts, who warn that the problem will worsen.