Russia said Tuesday that a fire broke out aboard a tanker in the Black Sea near the resort city of Sochi, prompting authorities to close beaches in Sirius.

The continuous monitoring of water and air quality is underway, Dmitry Plishkin, head of the Sirius federal territory administration, said in a statement, The Caspian Post reports, citing Anadolu Agency.

It did not say what caused the fire or whether anyone was injured. The tanker’s origin was not specified.

Telegram channels claimed that the vessel could have caught fire as a result of an attack by uncrewed surface vessels or strike drones.