Romanian F-16 fighter jets shot down two drones over the country's territorial waters on Saturday, the defense ministry said.
The drones were brought down days after two chemical tankers were hit by drones near Romania's Black Sea coast, the latest in a series of attacks highlighting risks to commercial shipping on NATO's eastern flank.
Both vessels were anchored near the Sulina canal, which links the Danube River to the Black Sea and is an export route for Ukraine.
NATO member Romania shares a 614-km border with Ukraine, much of it along the Danube, and has repeatedly reported Russian drone incursions into its airspace since Moscow's full-scale invasion of Ukraine in 2022.
Romania started shooting down such drones earlier this year.
Origin of drones not yet specified
The defense ministry said the two drones entered Romanian waters in the Black Sea on Saturday at 1459 GMT and 1501 GMT, respectively.
The ministry did not specify the origin of the drones.
The two tankers struck earlier this week were hit by Russian drones, a NATO military source told Reuters. Romanian officials are still searching for seven missing crew members.
At least five other cargo ships have been hit near the coasts of Romania and neighboring Bulgaria in the past 10 days, with 23 sailors reported dead or missing. Most of those incidents occurred outside NATO territorial waters.