Somali pirates freed a Saudi supertanker seized in the world's biggest ship hijacking for a $3 million ransom on Friday, an associate of the gang said.

The capture of the Sirius Star and its $100 million cargo of crude in November drew attention to a surge in piracy off Somalia that has brought global navies rushing to protect one of the world's most important shipping lanes.

Farah Osman, speaking from Haradheere port near where the tanker had been held, said the pirates had wanted more money but finally agreed to $3 million for the ship.