Heavily-armed Somali pirates have stepped up their attacks on vessels in Indian Ocean shipping lanes and the Gulf of Aden, capturing dozens of vessels, kidnapping hundreds of hostages and raking in millions of dollars in ransoms.

The French navy seized the suspected pirates, who were in three small boats, 1,000 kilometers (600 miles) off the coast of Somalia in the Indian Ocean.

“They confused the Nivose with a commercial ship and rushed toward it, to intercept it,” the spokesman said.

“The Nivose then put its own craft in the water with its commandos and sent out a helicopter and stopped these 11 pirates who were on these three boats.”

Two were small boats which the pirates use for attacks and the third was the mother ship which is used to transport supplies such as petrol, water and food.

The commandos also found guns and rockets on the boats.

“The pirates are currently on the Nivose,” he said.

“For the moment we don’t have any indication of what the European Union forces want to do with these pirates.”

A French naval patrol seized three more pirates in Seychelles’ waters on Saturday and handed them over to the coastguard, the islands’ president’s office said.

The attacks have disrupted U.N. aid supplies, driven up insurance costs and forced some firms to consider routing cargo between Europe and Asia around South Africa instead.

Naval forces from the United States, Europe and Asia have been deployed to protect merchant ships