"My men have hijacked a Turkish ship from the Indian Ocean and they are now heading towards me here in Haradheere," a purported spokesman for the pirates was quoted by the Reuters news agency as saying.
The pirate, identified only as Ali, was speaking by telephone from the Somali coastal town known to be used by pirates, Reuters reported.
The British Virgin islands ship was hijacked approximately 120 nautical miles off the coast of Oman also on Tuesday, Navfor said.
The crew of 23 Sri Lankans, a Filipino and a Syrian were held along with the 11,000-tonne Bermudan-flagged Talca, which had been heading from Egypt to Iran.
The pirates, who demand high ransom payments after hijackings, struck after the ship had passed through an international recommended transit corridor patrolled by warships and maritime patrol aircraft from Navfor, Nato, combined maritime forces and other navies.
John Harbour, a Navfor spokesman commander, said the attack were another example of pirates broadening the range of their operations as they find it hard to operate in the patrolled area.
Turkish cargo ships have been hijacked in the past and Nato-member Turkey's warships patrol the Gulf of Aden as part of an international mission to try to prevent piracy, which has surged off the Somali coast in recent years.
Globally in 2009, there were 406 reported incidents, in which 153 vessels were boarded and 49 were hijacked.
There were 84 attempted attacks and 120 vessels were fired on.
A total of 1,052 crew members were taken hostage and at least 68 crew members were injured while eight were killed.
In all, Somali pirates were held responsible for 217 acts of piracy in 2009, in which 47 vessels were hijacked and 867 crew members taken hostage.