The head of Ukraine's state-run nuclear operator has accused Russian forces of using a nuclear power plant they have captured as a military base and shelling Ukrainian positions from there.

President of Energoatom Petro Kotin said in an online interview with NHK on Friday that Russian forces recently deployed missile launchers within the site of the Zaporizhzhia nuclear power plant.

The facility in the southeastern Ukraine is one of the largest nuclear power plants in Europe. Russia took control of the plant in early March following intense and continued assaults.

Kotin criticized Russian troops for using a nuclear plant to shield themselves from attack, since Ukrainian forces can't retaliate because of stored nuclear fuel there and other factors.

The president said about 10,000 engineers and others are still working at the plant, and they are under strict Russian surveillance to make sure they don't cooperate with Ukrainian authorities.

Kotin said there is no guarantee of the safe operation of the plant, and that the situation is unacceptable. He has urged the international community to increase pressure on Russia to pull its troops out of the plant.