The French navy has seized nearly 10 tonnes of cocaine, worth $610m (£540m) off the coast of West Africa, French authorities have said.

Two French naval vessels operating as part of Operation Corymbe intercepted the enormous cocaine haul from an unflagged fishing vessel on Monday, acting on a tip-off from maritime intelligence, anti-drug authorities and the British National Crime Agency.

The Corymbe naval mission has been deployed by France in the Gulf of Guinea since 1990 to ensure security in an area where piracy is fairly common.

"9.6 tonnes of cocaine has been intercepted by two French ships," the French navy said.

It added that 54 tonnes of drugs had been intercepted in the area since the beginning of the year.

France's Atlantic Maritime Prefecture said "seamless cooperation by national and international actors" in the fight against narcotics had led to the "remarkable seizure" of 9.6 tonnes of cocaine.

The Gulf of Guinea, off the western coast of Africa, has seen multiple drug busts in recent months, with the region being a key transit point in the global trafficking of narcotics, in particular cocaine from South America being shipped to Europe.

The region was once considered the world's most dangerous area for maritime piracy, surpassing the waters off Somalia. Several Western countries have sent ships to help tackle piracy in the region.

A record cocaine seizure of 10.7 tonnes was made by the French navy in March last year, in what was the biggest interception of the illegal trade off the coast of West Africa.