Russian authorities struggled Tuesday to put out a massive fire in the southern Rostov region for a third consecutive day after an oil depot was hit by Ukrainian drones as Ukrainian forces push into Russia’s Kursk region.

The fire at the depot in the town of Proletarsk burned across an area of 10,000 square metres, according to Russian state news agencies. There are 500 firefighters involved in the operation, and 41 of them already have been hospitalised with injuries, according to the Russian state-owned news agency TASS, citing local officials.