Pirates have freed a Taiwanese vessel and its crew, kidnapped almost six months ago off the coast of Somalia.
Pirates have stepped up their activities off Somalia
Taiwanese and Kenyans were among those released. One crew member was killed shortly after the hijacking.
The release followed intervention by the US Navy, which has helped five ships in the area in the past week, all of which had been boarded by pirates.
The increased US activity is being seen as a sign of growing concern over Somali pirates.
The waters off the East African country are notorious for piracy - second only to Indonesia.
The freeing of the Taiwanese vessel came the day after two South Korean fishing boats were freed in the same area.
The South Korean boats were being escorted to Yemen under the guard of the US Navy.
Last week, US warships sank two boats that had been used by pirates to take over a Japanese merchant ship - although the ship itself is still under the pirates' control.
And the Americans also provided support for North Korean sailors, who managed to regain control of their ship from another group of pirates.
The US Navy itself is playing down the significance of this sequence of events.
But some maritime observers see it as a sign that Washington and others are paying more attention to the threat of piracy off the Horn of Africa.
After a lull last year, there has been a resurgence in incidents, says BBC world affairs correspondent Nick Childs.
These latest events may suggest a new focus for US warships, our correspondent adds.
Shipping sources say they hope US activity will help deter further attacks on vessels.
The waters off Somalia's coast lie close to crucial shipping lanes and are notorious for piracy.