Ukraine confirms loss of control over four naval drones before Constanța Port explosion last month, ministry says

Ukraine confirmed that it lost control of four naval drones due to suspected Russian electronic warfare a day before one of them exploded in the Constanța Port on June 5, according to Romania's Ministry of National Defense (MApN). The clarification came in response to questions sent by Romanian defense minister Radu Miruță following the incident.

According to MApN, the Ukrainian Defense Ministry said communications with four Sargan-3000 unmanned surface vessels (USVs) were lost on the afternoon of June 4 near Sevastopol, around 250 kilometers from the Romanian coast, while they were heading toward the eastern Black Sea.

From that point on, Ukrainian forces lost control of the drones and were unable to re-establish communications. Ukraine said the incident was isolated and was most likely caused by Russian electronic warfare.

“On the morning of June 5, at 9:54 a.m., the Ukrainian Navy informed the Romanian Naval Forces of the danger posed by the unmanned surface vessels (USVs) in the event of self-detonation and provided the scheduled time window for the self-destruction of the four drones. The loss of communications with the drones made it impossible to cancel the self-detonation command,” the Romanian ministry said.

One of the drones exploded at 10:27 a.m. near Berth 78 in the civilian section of Constanța Port after Romanian authorities had secured and evacuated the area. No injuries were reported.

According to the Romanian military, a second drone later self-detonated offshore under Coast Guard observation, while two more explosions were reported by commercial vessels farther out in the Black Sea. By 2:35 p.m., Romanian authorities concluded that all four drones had been destroyed.

Following the incident, Romania requested that Ukraine establish a permanent technical communication channel between the two countries' navies and agreed on new operational procedures for the timely exchange of information on risks in the Black Sea.

Romanian defense minister Radu Miruță also asked Ukraine to ensure that all naval drones deployed in the Black Sea are programmed to self-destruct in safe areas outside zones of interest to Romania if they drift off course for any reason.

MApN said it requested additional clarifications from the Ukrainian side while reiterating Romania's willingness to strengthen bilateral cooperation. The Romanian Naval Forces have also introduced additional measures to protect military port infrastructure, while several Romanian authorities are working to clarify the legal framework and responsibilities related to the security of civilian and military ports.