A new drone strike in southern Russia blamed on Ukraine caused a fire at an oil refinery, Krasnodar regional authorities said Sunday, adding that one person died after a suspected heart attack.

"The fire on the territory of the Slavyansk oil refinery has now been completely extinguished. According to preliminary information, one person died at the time of the drone attack, the preliminary cause of death being a heart attack," the Krasnodar region operational headquarters said on Telegram.

Roman Sinyagovsky, head of the Slavyansk Municipal District, said on Telegram one plant worker was injured and blamed the attack on Ukraine.