The Romanian Ministry of National Defence said the drone was thought to be "of the type used in the war in Ukraine". No injuries have been reported so far.
A naval drone exploded in the Romanian port city of Constanta on Friday morning.
In a statement, the Romanian Ministry of National Defence said the drone detonated at around 10:30 a.m. local time and that it was thought to be "of the type used in the war in Ukraine".
"The area had already been secured and cordoned off by forces from the Romanian Intelligence Service, the Coast Guard, and the Ministry of National Defense; at that time, the object was undergoing assessment and being secured," the ministry said.
It also confirmed that the drone was not part of the Romanian Army’s inventory and that it had not been involved in recent military exercises in the Black Sea area.
No injuries have been reported so far. An investigation into the incident is ongoing.
"The priority has been and remains the protection of human life and the security of the port infrastructure," Romanian President Nicușor Dan wrote on X in response to the news.
"Such particularly serious situations are the direct consequences of the war of aggression unleashed by Russia against Ukraine," he added.
Numerous emergency responders attended the scene, including police, border guards and firefighters. A Black Hawk helicopter was also mobilised to provide support, per Romania's Department for Emergency Situations.
It comes after a Russian drone carrying explosives crashed in the eastern Romanian city of Galați last week, causing a fire on the roof of a residential apartment block and injuring two people.
This is a developing story. Our journalists are working on further updates.