A Spanish frigate was steaming towards to an “alleged pirate-hijacked” Navibulgar bulker drifting in the Arabian Sea on Friday after it was boarded by unknown assailants.

The European Union naval force said the ESPS Victoria was heading to the 41,600-dwt Ruen (built 2016) to evaluate the situation after the Bulgarian government said the ship had been hijacked.

The Bulgarian News Agency (BTA) was citing Maria Gabriel — the country’s deputy prime minister and foreign minister — making comments to reporters in the parliament in Sofia on Friday.

“Eight Bulgarians are on the ship hijacked off the Yemeni island of Socotra,” BTA said.

Navibulgar did not respond to a request comment. Bulgarian news site maritime.bg, however, cites the company as confirming the incident.

“Based on the information gathered so far, the vessel is under the control of its captors... however, there is reason to believe that there is no immediate threat to the crew at this time,” the company was quoted as saying.

The crew of the Ruen includes nine seafarers from Myanmar and one Angolan citizen.

TradeWinds has been reporting since Thursday about the ship having been boarded by unknown assailants in the area.

The vessel is understood to have been drifting since.

According to Ambrey Analytics, all 18 crew are safe in the ship’s citadel, with surveillance and response operations ongoing.

Ambrey understands that six individuals boarded the vessel and that a Royal Navy Type 23 frigate was responding to the incident.

An Indian Maritime Patrol Aircraft (MPA) made contact with the Ruen and also observed a small boat that was adrift 1.5 miles from the bulker.

“The necessary has been done to transmit the information to all partners and institutions that we will count on to provide assistance,” the BTA quoted Gabriel as saying.

Who dunnit?

The identity of the persons who boarded the ship is unclear.

Yemen’s Houthi rebels have hijacked one ship since they began targeting vessels they believe to be controlled by Israeli interests or heading to Israel — Ray Car Carriers’ 5,100-ceu Galaxy Leader (built 2002).

The Malta-flagged Ruen does not appear to have sailed to Israel recently.

However, another Navibulgar handysize with a similar name — the 44,900-dwt Rojen (built 2019) — was in Ashdod when the Hamas-Israel war broke out in October.

The Houthis confirmed attacks on two other vessels in the Red Sea on Friday but they have not made any comment about the Ruen so far.

The incident might also be connected to suspected, resurgent Somali piracy in the area.

There have been numerous reports from ship masters of suspicious activity by small craft at the entrance to the Red Sea.

According to the United Kingdom Maritime Trade Operations (UKMTO), the vessel is heading towards Somalia.

Later on Friday and separately from the Ruen incident, the UKMTO warned of a Somali pirate group being active just off the country's coast near the Horn of Africa.

The US military attributed the attack and brief boarding on 26 November of Zodiac Maritime’s 20,000-dwt tanker Central Park (built 2015) to piracy, most probably by Somali nationals.

However, the US military’s interpretation has been met with scepticism by maritime intelligence sources.

Gary Dixon contributed to this article