Pirates operating in the Gulf of Guinea have kidnapped a total of 13 people on two European-flagged ships in the last three days.

Four crew members on a Greek oil tanker were kidnapped after pirates boarded the boat off the coast of Togo on Monday morning, while eight people were kidnapped from a Norwegian cargo boat during a similar incident off the coast of neighbouring Benin on Saturday.

The four kidnapped crew on the Greek ship consist of two Philippine nationals, one Greek and one Georgian, the Togolese navy said.

A security guard was also injured after being shot during the attack.

The vessel’s manager, European Product Carriers Ltd, confirmed in a statement that the vessel and remaining crew were safe.

"The safety and security of our people is of paramount importance to us and we are doing everything we can to ensure their prompt and safe release."

'We are reconsidering whether our ships should sail in this area'

On Saturday, nine crew members, including the ship's captain, were taken off the MV Bonita vessel while docked near Lome, as it prepared to unload gypsum.

The owners of the Norwegian ship, JJ Ugland, confirmed the entire crew is Filipino and said their families and been contacted and "will be kept informed".

Their condition has been described as "good, taking into account what they have been through".

It is not clear how many crew members avoided being kidnapped.

MV Bonita, a bulk carrier, eventually docked in the Port of Cotonou. The J.J. Ugland Companies via UER

Øystein Beisland, JJ Ugland's President, has reiterated that bringing the nine crewmembers back to safety is their "highest priority".

"The Ugland Emergency Response Team are handling this situation as per contingency plans, and they are in contact with relevant authorities."

"In light of the ongoing incident, we are reconsidering whether our ships should sail in this area".

#Alerte_Info Le Port Autonome de Cotonou a le regret de vous informer que samedi matin, le 2 novembre 2019, un acte de... Publiée par Port de Cotonou Officiel sur Dimanche 3 novembre 2019

In a Facebook post, the port of Cotonou in Togo said that "surveillance has been further strengthened" following Saturday's incident.

"The Autonomous Port of Cotonou presents its deepest sympathy to the hostages, their families and the other members of the Bonita crew."

‘The kidnap capital of the world right now’

According to the International Maritime Bureau (IMB), the Gulf of Guinea remains a "high risk area for piracy and armed robbery" in 2019.

This region, it added, makes up 86% of hostage-taking of crew members and 82% of crew kidnappings.

Cyrus Mody, Assistant Director at IMB, told Euronews the Gulf of Guinea is the "kidnap capital of the world right now".

Despite this, the number of crew taken hostage across the world from January to October has declined from 2018 (112 to 49).

ICC International Maritime Bureau Piracy and Armed Robbery against Ships, 1 January - 30 September 2019 (Google Maps)

"Although incidents are down, the Gulf of Guinea continues to be a concern for piracy and armed robbery-related activities with kidnappings of crew members increasing in both scale and frequency," IMB director Pottengal Mukundan said in a statement last month.

Other countries in the Gulf of Guinea which have seen instances of attacks on vessels include Cameroon, Equatorial Guinea and Ghana.

Nigeria has seen 29 separate ‘attacks’ from January to September this year, the most of any country in the world, while the only four hijackings of ships across the globe before October took place in the Gulf of Guinea.

Two categories of modus operandi

Mody told Euronews that the perpetrators of attacks on ships in the Gulf of Guinea are "skilled and well-armed".

"They more commonly attack a vessel to kidnap the crew, which is a lucrative business for pirates."

The IMB also reports that kidnapping crew can act as an insurance policy before the pirates can return to their 'safe haven'.

"A second motive is to attack a ship to steal cargo or the property of the ship and crew," said Mody.

The IMB is awaiting further information on the details behind the two latest incidents in Benin and Togo.

Shippers have reported several abductions in the region in recent months, including eight crew members taken from a German-owned vessel off Cameroon in August, and 10 Turkish sailors off the coast of Nigeria in July.

Pottengal Mukundan said: "it is important that shipmasters and owners continue to report all actual, attempted, and suspected incidents to ensure that an accurate picture of these attacks emerges and action is taken against these criminals before the incidents further escalate."

"We are encouraging ships and crews travelling in that region to understand the risks and employ sufficient safety recommendations," Mody added.

"But often these attacks are committed when there are other ships about or in the hours of darkness, which makes it extremely difficult for crew to identify a small vessel."

"By the time they realise they have been boarded, it is often too late."