A new wildfire broke out on Wednesday near a major nuclear research centre in the Russian town of Sarov, causing the plant's management to ask firefighters and troops to reverse their withdrawal.
"A new fire has broken out, caused by lightning which hit a pine tree," the centre said in a statement, as fires sweeping the centre of the country appeared to have eased their devastating advance.
Russia had begun withdrawing hundreds of firefighters and soldiers sent to douse the fires around Sarov, a town 500 km east of Moscow which houses the country's main nuclear research facility and is still closed to foreigners.
"The centre's director Valentin Kostioukov has asked the emergency situations ministry urgently to suspend the withdrawal of troops from Sarov and send in heavy equipment as reinforcements," it said.
"We began the withdrawal of some of the troops, but nature had a surprise in store for us in the form of a fire to the east, which is why we have to review our decisions," the Interfax news agency quoted Kostioukov as saying.
The total area enflamed by wildfires in central Russia has fallen by half since Tuesday, but there were still hundreds of wildfires raging, the emergencies ministry said.
Fires covering an area of 92,700 hectares were blazing in Russia, almost half of Tuesday's figure of 174,000 hectares, it said in a statement.