Ukraine and Russia are trading blame over a power outage at the Zaporizhzhia nuclear plant, which marks the first time Europe's largest nuclear station has been disconnected from Ukraine's national grid. 

The damage was caused by fires that Ukraine's state nuclear agency Energoatom said had interfered with power lines connecting the plant on Thursday, temporarily cutting Zaporizhzhia off from the grid.

"As a result, the station's two working power units were disconnected from the network," Energoatom said in a statement.

In a speech, Ukraine's President Volodymyr Zelenskyy blamed the damage on Russian shelling and accused Moscow of putting Ukraine and Europe "one step away" from disaster.

Energodar Mayor Dmytro Orlov has also posted a message on Telegram that the city had been left without electricity and water following shelling by Russian forces.

However, the Russian defense ministry said in a daily report earlier on Thursday that Ukrainian troops continue to shell the Zaporizhzhia NPP and Energodar city. In addition, the Russian side blamed Ukraine's attack for the outage.

The plant has been controlled by Russian forces since March, although Ukrainian technicians still operate it. The shutdown of power units at the plant indicates the need to deliver the International Atomic Energy Agency specialists to the station as soon as possible, the UN said.

The IAEA Director-General Rafael Grossi also said he hoped IAEA's inspection mission would take place "within days" once a deal has been reached on gaining access to the site.

The visit might come in late August or early September, Russia's TASS news agency reported.