Hundreds of Russian firefighters in the southern Rostov region were battling a massive fire at an oil depot Tuesday for a third day after it was hit in a Ukrainian drone attack.
Russia has said dozens of firefighters have been injured in the blaze, which has intensified since the fuel storage facility in the city of Proletarsk was struck on Sunday morning.
Around 520 firefighters were now involved in tackling the fire, the state-run TASS news agency reported Tuesday, citing the head of the local administration.
The fire had spread to an area of 10,000 square metres, it added.
Videos on social media showed a massive orange flame over an industrial site, with thick dark smoke rising into the air.
A local state of emergency was introduced on Monday.
Kyiv has targeted Russian oil infrastructure throughout the Kremlin's Ukraine offensive and Sunday's strike came in the midst of its incursion into Russia's Kursk region.
Proletarsk lies in the Rostov region, some 200 kilometres from the Ukraine border.
Four giant Il-76 planes were also on their way from the regional hub of Rostov-on-Don to help try to put out the fire, TASS quoted city head Valery Gornich as saying.
"The heat is such that fire engines cannot come close," he said.
He added that there is "no threat of an explosion, no threat to people and there are no evacuations."
Around 20 of the site's 74 storage tanks, each with a capacity of 5,000 cubic metres, were on fire, the RIA Novosti state news agency quoted Gornich as saying.
Rostov Governor Vasily Golubev said Monday that 41 firefighters needed medical attention, with several having moderate to severe burns. No civilians have been reported injured.
Proletarsk is a city of some 20,000 people.
The Rostov region -- a major hub for Moscow's Ukraine operation -- has been heavily targeted by Kyiv.