Pirates have kidnapped 10 crew members from a St Kitts-flagged general cargoship boarded off Nigeria.

The 2,500-dwt Milan (built 1982) came under attack on Wednesday evening, 14 nautical miles (26 km) north-west of Chevron's Pennington Terminal and 10 nautical miles from shore, security consultancies Ambrey and Dryad Global said.

The vessel was in transit from Escravos in Nigeria to Douala, Cameroon.

AIS data indicates the Milan was in a southbound transit when it was stopped.

The precise time of the attack remains unclear, Dryad said.

Sixth boarding off Nigeria in 2020

Manager Miro Shipping of Lebanon could not be contacted.

This is the sixth boarding in Nigerian territorial waters this year.

The confirmation of the kidnapping brings to 128 the number of seafarers taken in 24 attacks this year in the Gulf of Guinea.

"Recent established regional trends have shown an increase in boarding incidents beyond the Nigerian exclusive enterprise zone, with Nigerian pirate action groups seeking to operate beyond the traditional heartland," said Dryad Global.

The groups have failed in kidnapping attempts involving larger tankers hundreds of kilometres offshore in recent weeks.

However, they have had more success with smaller ships nearer to coasts.

Last week, three seafarers were abducted from the 400-dwt bunker tanker Stelios K (built 1995) 40 nautical miles south of Lome in Togo.

But industry observers said this was more likely to be as a result of a commercial dispute than a random attack.

Earlier this month, five crew members were kidnapped in the Gulf of Guinea from the 1,700-dwt general cargoship AM Delta (built 1992) off Nigeria.

And three days before that, a gang kidnapped 14 Chinese crew members from a heavylift vessel. The 48,127-dwt Liberian-flagged Zhen Hua 7 (built 1998) was raided northwest of Sao Tome.