Pirates off Nigeria's coast kidnapped 15 sailors from a Turkish container ship on Saturday, in a brazen and violent attack that was farther from shore than usual.
One sailor, an Azerbaijani citizen, was killed in the raid, while those kidnapped are from Turkey, according to the respective governments and a crew list seen by Reuters.
Accounts from crew, family members and security sources described a sophisticated and well-orchestrated attack, in which armed pirates boarded the ship and breached its protective citadel, possibly with explosives.
Three sailors remain on the Mozart ship, which by Sunday evening was receiving assistance in Gabonese waters off central Africa.
"The ship is in our waters and our sailors are assisting a few nautical miles from Port Gentil," said Gabon's presidency spokesman Jessye Ella Ekogha, without providing further detail.
The Liberian-flagged vessel was headed to Cape Town from Lagos when it was attacked in the Gulf of Guinea, 160 kilometers (100 miles) off Sao Tome island on Saturday, maritime reports showed.
The ship's fourth captain, Furkan Yaren, had been "cruising blindly" toward Gabon with damage to the ship's controls and only the radar working, according to state-run news agency Anadolu. The pirates beat crew members, and left him with an injured leg while another still aboard the ship had shrapnel wounds, Yaren said.
Turkish media cited Istanbul-based ship owner Boden company as saying the owners and operators of the vessel were abducted at gunpoint. Boden was not immediately available.
Ambrey, a security company, said four armed men boarded the Mozart and entered the citadel -- where crew are advised to hide in any attack -- from a deck atop the cabin.
Turkish President Tayyip Erdogan's office said on Sunday he was orchestrating officials in the "rescue of kidnapped ship personnel." Erdogan spoke twice by phone with Yaren, who remained aboard after the attack, his office said.
Edward Yeibo, a Nigerian Navy commander, said he was not aware of the attack and was seeking details. The Lagos naval command office and a spokesman for Nigeria's maritime regulator were not immediately available.
Pirates in the Gulf, which borders more than a dozen countries, kidnapped 130 sailors in 22 incidents last year, accounting for all but five of those seized worldwide, according to an International Maritime Bureau report.
The attack on the Mozart could raise international pressure on Nigeria to do more to protect shippers, which have called for tougher action in recent weeks, analysts said.
"The fact that someone died, the number of people taken and the apparent use of explosives to breach the ship's citadel means it is a potential game-changer," said David Johnson, CEO of the UK-based EOS Risk Group.
"It's clearly quite sophisticated and if pirates have decided to use munitions it's a big move," he said. There is "no doubt" those kidnapped will be taken back to Nigeria's Delta and Turkey will have little hope stopping it, he added.
Turkey's foreign ministry said the pirates had not made any contact with Ankara.
Seyit Kaya, brother of the ship's kidnapped 42-year-old captain Mustafa Kaya, a father of two, said in an interview he awaited details from the ship's owner on any possible ransom.
"Since that area is where many attacks take place, they take cautions against pirates," said Kaya, who is also a sailor.