ANKARA, Turkey—A Guinea-Bissau flagged cargo ship with 14 crew members on board sank off Turkey’s Mediterranean coast on Wednesday, killing at least three of them. Five people were rescued while efforts continued to find the other missing crew, officials and news reports said.

The Joe 2 sank off the coast of Kumluca, in Antalya Province, while heading to Ukraine from the Turkish port of Iskenderun, said Gov. Ersin Yazici said. It was transporting aluminum, according to the state-run Anadolu Agency.

The cause of the ship sinking was not immediately clear. An investigation has been launched by the chief prosecutor’s office for Kumluca.

The Turkish Coast Guard Command said it received a distress call at 3:47 a.m. and dispatched a vessel, several boats, and two helicopters. Two crew members were rescued by the coast guard helicopters while three others were saved by other vessels in the area, it said.

All of the crew were Syrian nationals.

The rescue efforts were being hampered by a storm, Anadolu reported.