Officials in Ukraine say that there has been a spike in radiation levels in the Chernobyl restricted zone due to a fire in the area.
Radiation levels are above normal in the fire's centre.
Two planes along with a helicopter and more than 100 firefighters are fighting the fire.
There is still a fire burning covering an area of 20 hectares.
The fire is under control.
Police officers found the suspect that said he was burning the dry grass for fun when the wind caused the flames to quickly spread out of control.
The Chernobyl disaster was a nuclear accident that occurred on Saturday 26 April 1986, at the No. 4 nuclear reactor in the Chernobyl Nuclear Power Plant, near the city of Pripyat in the north of the Ukrainian SSR.