ABIDJAN (AFP) ― A French tanker with a mostly African crew has been hijacked off Ivory Coast, Ivorian and French officials said Monday, amid concern the area is becoming a new pirate hotspot.

Ivory Coast officials said that 15 African and two Asian sailors were aboard the Gascogne tanker ship, which was sailing under a Luxembourg flag, though the French government said earlier that the crew consisted of 19 Togolese sailors.

Sea Tankers, the French owners of the vessel, lost communication with the ship on Sunday morning. They have been unable to re-establish contact, they said.

“The ship was indeed hijacked 139 kilometers from Abidjan, in Ivorian waters, by an armed gang,” Colonel Bertin Koffi Tano, Ivory Coast’s director of maritime affairs, said during a press conference, adding that the vessel appeared to be somewhere off the coast of Nigeria on Monday.

The tanker, which had been chartered by a South Korean company, had 3,000 tons of diesel fuel onboard at the port in the economic capital Abidjan a few days ago, but had already offloaded some onto another ship before being seized, Tano said.

He said the crew was made up of seven Togolese, four men from Benin, two Senegalese, two Ivorians, a Chinese and a South Korean.

Paris said it had yet to receive any demands from the pirates.

“It’s very worrying,” Frederic Cuvillier, the French minister for transport and the maritime sector, told reporters in France, adding that the Defense Ministry had been “mobilized,” without elaborating.

The latest hijacking marks the third such incident in recent months in the Ivory Coast after pirates seized a Panama-flagged oil tanker anchored in Abidjan last month, and hijacked a Greek tanker in the same city in October, looting the vessel before releasing it.

“It appears pirates are moving towards the Ivory Coast because Nigeria and Benin have increased patrols in the Gulf of Guinea,” said Noel Choong, head of the International Maritime Bureau piracy reporting centre.

The Kuala Lumpur-based maritime watchdog raised the alarm about the Gascogne and issued a warning to other ships, he added.

Despite fears pirates are increasingly targeting the waters off Ivory Coast, the county’s authorities said they have no vessels to monitor Ivorian waters.

Meanwhile, Sea Tankers expressed concern for the safety of the crew in a statement. Its president, Peter Raes, told FR3-Aquitaine television in France he hoped the pirates would “unload the ship somewhere” and make their escape.

The Gulf of Guinea, which includes waters off Nigeria, Africa’s largest oil producer, recorded 62 pirate attacks in 2012, including hijackings, kidnappings and killings.

The attacks have mostly taken place in Nigeria but they appear to be spreading to other areas.

Choong said he had recorded two more attacks in the Gulf in recent days, one of which left a seafarer with gunshot wounds.

Pirates usually target fuel cargo, loading it onto other ships to sell on the lucrative black market, rather than seeking a ransom to release ships.

The “armed groups” who carry out these attacks “know that there is not much oversight on this side of the Gulf of Guinea,” said Colonel Mamadou Mariko, technical director of the Maritime Organization of Western and Central Africa, based in Abidjan.

The growing pirate threat off Ivory Coast was becoming “urgent,” he warned, calling on Abidjan to tackle the problem “head-on.”