A Maltese-flagged merchant ship that was hijacked last week in the Arabian Sea with 18 crew on board is now off the coast of Somalia, the European Union's maritime security force said Tuesday. One crew member has been evacuated for medical care.

The bulk carrier Ruen remains under the control of the hijackers, whose identity and demands are unknown, the EU Naval Force said in a statement. It did not give details on the condition of the crew member who was taken off the vessel on Monday and moved to an Indian navy ship that has been shadowing the Ruen.

An Indian maritime patrol plane spotted the Ruen a day after its hijacking last Thursday and made radio contact with the crew, who had locked themselves in a safe room. The hijackers broke into the safe room and "extracted the crew" hours later, the EU Naval Force said.

The Ruen, which is managed by Bulgarian shipping company Navibulgar, was off the Yemeni island of Socotra near the Horn of Africa when it was boarded, the private intelligence firm Ambrey and the United Kingdom Maritime Trade Operations said. Bulgarian authorities said the ship’s crew were Angolan, Bulgarian and Myanmar nationals.

The 185-meter (606-foot) Ruen was carrying a cargo of metals from the port of Gwangyang in South Korea, the EU Naval Force said. It had been headed to the Turkish port of Gemlik. The captain confirmed the hijacking by sending a mayday alert to the EU Naval Force’s command center.

The vessel has now moved southwest toward the coast of Somalia, according to the EU force.

Suspicion has fallen on Somali pirates, whose attacks have decreased markedly in recent years. They may be more active again. The Pentagon has said that five armed assailants who seized a commercial ship near Yemen late last month were likely Somali nationals and not Iranian-backed Houthi rebels, who were first suspected to be responsible.

The Yemen-based Houthi rebels have escalated their attacks on ships passing through the Red Sea during the Israel-Hamas war, impacting global trade. The U.S. said Tuesday that it and a host of other nations are creating a force to protect ships transiting the Red Sea that have come under attack from Houthi-controlled areas of Yemen.

But Somalia’s maritime police have also intensified their patrols in recent weeks following the Pentagon's assessment of last month's attempted hijacking as fears grow of a resurgence of piracy by Somali nationals.

A Spanish frigate from the EU Naval Force and a Japanese naval vessel that is under the multinational Combined Maritime Forces command have moved to the vicinity of the hijacked Ruen to join the Indian navy vessel. It is being “continuously monitored” by the ships and a 5-meter-long (16-foot) drone used by the EU force.