Emergency services were battling on Tuesday to prevent Ukraine’s largest forest fire since 1992 from spreading towards the abandoned Chernobyl nuclear power plant, Prime Minister Arseny Yatseniuk said.

Earlier, the interior ministry had warned that high winds were blowing the fire in northern Ukraine towards Chernobyl, where in 1986 a reactor fire led to the world’s worst nuclear disaster.

A 30 km (18.6 miles) exclusion zone remains in place around the plant, which remains contaminated by radioactive particles.

“The situation is being controlled, but this is the biggest fire since 1992. We’ve not had this scale of fire,” Ukraine’s Interfax news agency reported Yatseniuk as telling journalists.

“It is around 20 kilometers (from the fire) to the plant. Our emergency services are actively working there to prevent the fire spreading further,” he said.

In February, international experts warned that a large amount of dangerous isotopes remained in the forests near Chernobyl, which could be spread by forest fires.

“Wildfires … pose a high risk of redistributing radioactivity,” according to a paper published in Ecological Monographs, titled ‘Fire evolution in the radioactive forests of Ukraine and Belarus: future risks for the population and the environment.’

Chernobyl’s Reactor 4, the epicenter of the 1986 blast, is covered with a concrete casement that the Ukrainian authorities plan to replace by 2016.