Nigerian militants have attacked a new shipyard in Akwa Ibom state, damaging a dredger.

The Norfin Offshore Shipyard facility was due to be inaugurated on 23 January, but it has been postponed by a week due to the actions of the gunmen.

Security consultancy Ambrey said the armed criminals arrived in speedboats, firing shots into the air and throwing petrol bombs.

They reportedly hit a ship named as the Norfin Power 1.

Imagery seen by Ambrey shows the vessel sustained significant fire damage totalling NGN 60m ($160,000).

No injuries were reported and no arrests were made.

The yard had previously been subjected to an extortion demand of NGN 20m by the gang.

The Punch newspaper said the attack took place on Monday morning.

The yard's chairman, Iniekong Udonwa, told the newspaper that the criminal group told the yard it could not start operations without paying them.

Who's in charge?

"They keep telling our staff to tell the government of Akwa Ibom to reach out to them since they are in charge of both Rivers and Akwa Ibom states," he added.

"Where do they expect me to get NGN 20m for them after destroying our machine worth NGN 60m?"

The yard is the second established in the country by Norfin Offshore of Singapore and Nigerian investors.

The total cost will be $20m by the time it is fully operational.

More than 100 workers are employed there.

The incident is just another illustration of the problems Nigeria faces in ridding the country of organised gangs, which also plague international shipping.