The emergency department of the Seversky district said the incident occurred around 4 a.m. on Friday. The accident caused damage to utility structures within the refinery. The fire, which spread over an area of ​​50 square metres, was extinguished, Xinhua news agency reported.

"Preliminary reports indicate that two people were injured," the department said.

Krasnodar Governor Veniamin Kondratyev confirmed that administrative buildings at the refinery were damaged.

A boiler house near the Yuzhny bus station in Krasnodar was also affected.

"Sadly, there are injured workers at these sites. They are receiving all necessary medical assistance," Kondratyev said on his Telegram channel.

Preliminary reports from the Krasnodar Regional Operational Headquarters indicate that several municipalities in the region came under large-scale attack by Ukrainian armed forces early Friday.

The operational headquarters also reported that four people were injured in Krasnodar due to debris falling from the drone.