Kateryna Pavlova, acting head of the State Agency of Ukraine on Exclusion Zone Management, told the Associated Press news agency that they “cannot say the fire is contained”.

“We have been working all night, digging firebreaks around the plant to protect it from fire,” she said.

On 5 April Yegor Firsov, acting head of Ukraine’s state ecological inspection service, said in a Facebook post that radiation levels in the area had risen substantially above normal.

Government officials later rejected this finding, and said the levels in the area were “within normal limits”. Mr Firsov also withdrew his remarks.