Orthodox priests brought an icon to the scene of a huge fuel depot fire in southern Russia sparked by a Ukrainian drone attack in the hope it would help tame its flames, the local diocese said on Wednesday.

The icon of the Unburnt Bush is considered by Christians in Russia as a talisman against fire.

Reuters

The giant fire at the Proletarsk fuel depot in Rostov region has been burning since Sunday despite efforts by firefighters to douse its flames.  

Around 20 of 74 storage tanks were on fire, the RIA news agency reported on Tuesday, citing local administration boss Valery Gornich.

More than 500 firefighters were tackling the blaze, Gornich told the TASS news agency. 

An image released on Wednesday showed two Orthodox priests standing in a field on either side of a wooden stand holding the large icon as a thick plume of black and grey smoke rose into the sky from the depot behind them.  

"The (priests) spoke with the firefighters and blessed all the fire equipment," the local Volgodonsk eparchy told Reuters in emailed comments.

Local people have complained on social media about how polluted the air has become due to the fire. The authorities have said the level of harmful substances in the air is within permitted norms.

Vasily Golubev, the regional governor, said on Monday that 41 firefighters had sought medical treatment, including five who had been placed in emergency care.