The mayor of the Russian Black Sea port city of Novorossiisk issued a sea drone alert on Thursday morning, he said on the Telegram messaging app.
Mayor Andrei Kravchenko urged locals to stay away from the shoreline. Ukrainian sea drones have in the past attacked Russian ships near the port, disrupting traffic.
Novorossiisk is Russia's largest Black Sea port and a key outlet for crude oil and oil product exports in Russia's south. It also loads oil coming from Kazakhstan and Azerbaijan and handles grain, coal, fertilizers, timber, containers, food and chemical cargoes.
Separately, the Russian-appointed governor of the city of Sevastopol in Crimea, Mikhail Razvozhayev, said Russia forces destroyed a Ukrainian sea drone in the Black Sea near the city.
(Reuters - Reporting by Reuters; Editing by Christopher Cushing and Christian Schmollinger)