Ten Somalis arrested by the US navy have been flown to the Kenyan port of Mombasa, where they are to be charged.
There were some 35 piracy incidents last year
Kenyan sailors, taken hostage on a ship carrying UN food aid to Somalia, have reportedly identified some of the men.
Meanwhile, three more Taiwanese fishing boats seized by pirates off the Somali coast have been freed, officials say.
Somali waters are the world's most dangerous for pirate attacks, according to international shipping groups. There has been no government for 15 years.
The men were caught earlier this month by guided missile destroyer USS Winston S Churchill after receiving a report of piracy off the Somali coast.
The Indian crew on board the ship was freed. They had attracted the attention of the US navy by writing "Help" on the side of the ship, reports Kenya's Daily Nation newspaper.
In the Taiwanese capital, Taipei, foreign ministry official Michel Lu told the AFP news agency: "The three ships have set sail from Somalia, and the crew are all safe."
The four vessels carried a total of 62 crew from Taiwan, China, the Philippines, Indonesia and Vietnam.
Another Taiwanese ship was freed last week.
Piracy, including hijackings and hostage-taking, has become common off anarchic Somalia.
An attack late last year against a luxury cruise liner was repelled by an ear-splitting acoustic device.
Shipping companies say there have been 35 incidents of piracy off the Indian Ocean coast of Somalia in the past nine months.
The transitional Somali government has signed a $50m (£28m) two-year deal with a private US marine security company to carry out coastal patrols.
However, it is not clear where this money would come from, as the government has not effectively taken office. The security company has not started work.