Progress IV sinking leaves Romania with a successful rescue and an open investigation

The location creates legal questions, not a ready attribution

Published accounts differ slightly on the vessel’s location. The Romanian Naval Authority reported about 15 nautical miles from Sfântu Gheorghe, while Reuters placed it roughly 20 nautical miles offshore. Investigators will need to reconcile the underlying coordinates, although both accounts place the ship beyond Romania’s territorial sea.

An exclusive economic zone is not national territory. Under Part V of UNCLOS, Romania has specified rights over natural resources and jurisdiction in fields including marine environmental protection. Other states retain freedom of navigation. The rescue obligation does not arise simply because the vessel was in Romania’s EEZ, and criminal jurisdiction over the suspected acts requires a separate legal assessment. The location therefore cannot determine who caused the loss or whether Romania itself was the intended target.

Safety investigators and prosecutors have different tasks

On 28 August, prosecutors in Constanța opened an in-rem criminal investigation. The possible offences include pollution, destruction of a ship, eight counts of bodily injury and the use of a civilian drone carrying explosives. An in-rem investigation concerns suspected acts before responsibility is assigned. The drone scenario is one line of inquiry rather than a finding about the weapon, perpetrator or intent.

“The coordinated operation brought every crew member to safety that evening. Investigators have not yet established why the ship went down.”

President Nicușor Dan said the vessel appeared to have been hit, while stressing that authorities did not know by whom or by what. Public attribution would become more persuasive if investigators produced mutually consistent hull analysis, recovered fragments, sensor records and a verified incident timeline. None of those findings has been released so far.

The total loss also requires a marine safety investigation under the IMO casualty framework. Its purpose is to identify the circumstances and contributing factors so that similar casualties can be prevented. It does not assign criminal blame or civil liability. The criminal investigation has the separate task of determining whether an offence occurred and who may be responsible. Keeping these functions distinct will help prevent preliminary safety information from being presented as proof of an attack.

Russia’s war makes the inquiry urgent

The sinking occurred amid Russia’s continuing war of aggression against Ukraine and repeated Russian attacks on Ukrainian ports and commercial shipping. Two days earlier, Russia’s defence ministry claimed strikes on five vessels and port and fuel facilities in Ukraine’s Odesa region. Reuters could not independently verify the claim. It establishes neither a connection to Progress IV nor responsibility for the later incident in Romania’s exclusive economic zone.

That wider threat makes a hostile strike a credible possibility and gives Romania reason to investigate quickly. Incident-specific evidence must still carry the attribution. The current record answers the immediate safety question: the alert reached MRCC, assets were deployed and all 12 people were recovered within three hours. Whether Romanian systems detected the danger before the alert, could have warned the vessel or recorded useful tracking data remains unknown. A published marine casualty report can explain how the ship was lost, while a criminal finding supported by forensic and sensor evidence could establish a deliberate attack and identify responsibility. Until those inquiries provide such evidence, Progress IV remains a successful rescue followed by an unexplained sinking.