Russia's paratroops have seized control of the defunct Chernobyl nuclear power plant and its surrounding areas in Ukraine.

Defense ministry spokesperson Igor Konashenkov made the announcement on Friday.

On the same day, Ukrainian nuclear regulators said that a monitoring system in the exclusion zone around the plant showed abnormal radiation levels at a significant number of observation points. They said they could not determine the reason because the area had been occupied by Russian forces.

But the Russian ministry insisted that radiation levels in the area are normal. It said that it agreed with the Ukrainian side to jointly ensure the safety of the plant.

Reuters and other news agencies quoted experts as saying that the change in radiation levels was due to the movement of heavy military equipment in the area lifting radioactive dust into the air.