The United Nations Security Council has renewed its authorisation for the use of military force against pirates operating off Somalia, enabling the European Union to begin an air and naval operation next week.

The US-drafted resolution, which was adopted unanimously, extends for one year the right of countries with permission from Somalia's transitional government to pursue and attack pirates in Somali waters.

"The international community is sending a very strong signal of its determination to deal with piracy," said Jean-Maurice Ripert, the French ambassador to the UN.

The EU is set to send warships to patrol Somalia's Gulf of Aden and Indian Ocean waters, where a rise in piracy is threatening to stifle one of the world's busiest maritime trade routes.

"We think it will act both as a deterrent and also [provide] some immediate capacity to follow on and pursue pirates, if we can catch them," Ripert said.

However, the issue of who has jurisdiction over captured pirates and where they can be prosecuted remains unresolved.

Previous mission

The European mission is aimed at protecting ships that carry World Food Programme supplies to feed about three million Somalis who depend on food aid, as well as escorting shipping frigates in the area.

The naval force, backed by patrolling aircraft, will be commanded by British forces.

There have been about 95 pirate attacks in Somali waters this year, with about 40 ships captured, including a Saudi tanker holding $100 million of oil.

There are already several international naval operations along the Horn of Africa, including a Nato mission to counter piracy, but they have done little to deter hijackers, who have been paid tens of millions of dollars in ransoms by firms seeking to free hijacked ships.