Dozens of ships, mainly merchant vessels, have been seized by gangs off Somalia's 3,700-kilometre (2,300-mile) coastline in recent years, despite the presence of Western navies deployed in the region to fight terrorism.
The pirates travel in speedboats and are armed with automatic weapons and rocket-propelled grenades. They sometimes hold ships for weeks until they are released for large ransoms paid by governments or owners.
In recent months, a multinational taskforce based in Djibouti has been patrolling parts of the Gulf of Aden and the Red Sea, where a pirate mothership is believed to be operating.
French naval commandos have taken action against pirates who seized two sailing vessels with French citizens aboard and arrested a dozen suspects.
They were brought to France and are awaiting trial on charges of hijacking, hostage-taking and armed robbery, which carry life sentences.
Some pirates have justified their actions by claiming that, in the absence of a functional central authority in Somalia, they were battling illegal fishing and toxic waste dumping by foreign countries.
Somalia has been without an effective central authority since the 1991 ouster of president Mohamed Siad Barre set off a deadly power struggle that has defied more than a dozen peace initiatives.
