Ukrainian drone strikes on the southern Rostov region killed three people, including two sailors aboard a cargo ship, regional authorities said early Thursday.

Rostov region Governor Yury Slyusar said a drone struck a cargo vessel moored along the Don River in Rostov-on-Don, killing two crew members and injuring three others.

Mayor Alexander Skryabin said it was the first reported death in the city caused by a drone attack since the start of Russia’s full-scale invasion of Ukraine.

In a separate drone strike, Governor Slyusar said a person was killed and six others were wounded in the town of Bataysk, just south of Rostov-on-Don.

Russia’s Defense Ministry said its air defense systems destroyed three Ukrainian drones over the Rostov region overnight. Overall, it reported downing 47 Ukrainian drones over three Russian regions, annexed Crimea and the Black Sea.

The strikes come amid Ukraine’s ongoing campaign targeting Russian energy infrastructure, including vessels and ports, as well as major oil terminals in the south of the country.

In response to those attacks, Russia has stepped up its own strikes on Ukrainian cities, targeting ports like Odesa on the Black Sea.