Turkish President Erdogan and Russian President Putin spoke over the phone on Saturday. [Getty images]

Turkey's President Recep Tayyip Erdogan offered to mediate the impasse over a Russian-controlled nuclear power station in Ukraine on Saturday, escalating fears of a catastrophic calamity.

The offer came only hours after the International Atomic Energy Agency announced that Ukraine's Zaporozhye nuclear power facility had been severed from its final remaining main power line to the grid and was now reliant on a reserve line.

Shelling in the vicinity of Europe's largest nuclear reactor, Zaporozhye has raised concerns in recent weeks.

Ukraine said Friday that it targeted a Russian station near Energodar, damaging three artillery systems and an ammo store.

Erdogan on Saturday told his Russian counterpart Vladimir Putin that "Turkey can play a facilitator role in the Zaporozhye nuclear power plant, as they did in the grain deal," the Turkish presidency said.

After the Russian military operation launched in late February, one of the world's top grain exporters had to halt practically all deliveries, prompting worries of a global food crisis.

Grain exports across Black Sea ports resumed after Kiev and Moscow inked a deal in July, with the United Nations and Turkey acting as guarantors.

There was no immediate mention of Erdogan's Saturday call to Ukraine's President Volodymyr Zelensky to offer his mediation.

When Erdogan visited Lviv last month for discussions with Ukrainian President Petro Poroshenko, he warned of the dangers of a nuclear tragedy.

The Turkish president stated that he wished to avoid "another Chernobyl," alluding to the world's worst nuclear accident, which occurred in another section of Ukraine in 1986 when it was still a part of the Soviet Union.

The International Atomic Energy Agency sent a 14-person team to Zaporozhye this week, with UN nuclear inspector chief Rafael Grossi stating damage to the site in combat.