It was seized about a day after passing through the warship-patrolled transit corridor in the Gulf of Aden, which commercial vessels are encouraged to use.

Nilgun Yamaner said "the pirates abandoned the ship, the Frigia, at 7:25 am (0425 GMT) this morning. It has since been under the captain's control," as she represents the ship's owners, the Istanbul-based Kayra shipping company.

The ship's crew of 19 Turks and two Ukranians were in good health, and "We have talked to the captain. They are all very excited and happy," Yamaner added in an AFP report.

After its release, the Frigia left the shores of Somalia to meet the Turkish frigate Gelibolu, which serves as part of a NATO anti-piracy force in the region, and "the current crew will be sent home after their ordeal. The vessel will continue on to Thailand with a new crew to deliver its load," Yamaner said.

Naval missions, including the European Union's Atlanta deployment, have boasted success in curbing attacks but the number of hijacked ships and detained seafarers remains at one of its highest levels since Somali piracy surged in 2007.

Unofficial figures show that 2009 was the most prolific year yet for Somali pirates, with more than 200 attacks -- including 68 successful hijackings -- and a total in ransoms paid believed to exceed 50 million dollars.