Ukraine blames Russian jamming for drone that exploded in Romania's Constanța port
Kyiv says it lost control of four naval drones near Sevastopol on 4 June after Russian electronic warfare, leading to an explosion in the Romanian port the next day.
Ukraine's explanation
On 3 July 2026, Romania's Ministry of National Defence (MApN) announced it had received Ukraine's official response to 14 questions submitted by Defence Minister Radu Miruță regarding the 5 June drone explosion in Constanța port. Ukraine confirmed that on the afternoon of 4 June, its forces lost communication with four Sargan-3000 unmanned surface vessels (USVs) near Sevastopol, approximately 250 km from the Romanian coastline. The drones were en route to the eastern Black Sea. From that moment, Ukrainian authorities had no control over their trajectories and could not re-establish the link.
The following morning, at 09:54 on 5 June, the Ukrainian Navy informed the Romanian Navy of the risk posed by the drones' self-destruct sequences and transmitted the programmed detonation interval. Because communication had been lost, cancelling the self-destruct command was impossible.
This incident is isolated, most likely caused by electronic warfare actions of the Russian Federation.
Timeline of the port incident
Romanian authorities first detected a floating object near Dana 78 in Constanța port at 06:20 on 5 June, when the Maritime Coordination Centre alerted the Naval Component Command. The Coast Guard, the Romanian Intelligence Service (SRI), and explosive ordnance disposal (EOD) teams were mobilised. After Ukraine's warning at 09:54, the area was evacuated. At 10:27, one drone exploded inside the port. No casualties were reported. Three further explosions occurred later at sea, outside the port. By 14:35, Romanian forces confirmed the destruction of all four drones and ended the intervention.
- Ukraine loses communication with four Sargan-3000 naval drones near Sevastopol, 250 km from Romanian shore.
- Romanian Maritime Coordination Centre reports floating object near Dana 78 in Constanța port.
- Ukrainian Navy informs Romanian Navy of self-detonation risk; evacuation begins.
- One drone explodes inside Constanța port; no casualties.
- Romanian authorities end intervention after confirming destruction of all four drones.
Romania's response and demands
Following the incident, MApN requested the opening of a permanent technical communication channel between the Romanian and Ukrainian navies, along with operational procedures for timely mutual notification of Black Sea risks. Defence Minister Miruță formally asked Ukraine to programme all naval drones launched in the Black Sea to self-destruct in safe zones outside Romanian areas of interest, should they lose control for any reason. Romania thanked Ukraine for the information provided, requested additional clarifications, and reiterated its readiness for closer cooperation.
