"The government will ensure that the nuclear facilities at the plant... are integrated as federal property," the executive order said.

The power station has been occupied by Moscow's forces since March and is close to the front line.

Putin's decree came as the head of the International Atomic Energy Agency (IAEA) Rafael Grossi said he was travelling to Ukraine for talks on the Zaporizhzhia plant.

Grossi will "continue his consultations" on setting up a nuclear safety and protection zone around the power station, the IAEA said Tuesday.

Ukrainian state nuclear agency Energoatom said earlier Wednesday, after the plant's operating company was moved to Moscow, that Russia was "creating pseudo-enterprises with the names of Ukrainian companies".

"It's just a pity that they are trying to involve Ukrainian nuclear professionals, who have been heroically working under... occupation for more than seven months" at the Zaporizhzhia plant, Energoatom said on social media.

Russian forces detained the chief of the power station, Ihor Murashov, for two days before releasing him on Monday.

But Grossi said his detention and release posed "no risk at all" to operations at the plant.

Shelling has hit in the vicinity of the power station in recent months, with Ukraine and Russia blaming each other for the attacks that have raised fears of a nuclear disaster.