The statement did not say what kind of teams were involved or whether a ransom was paid. The sailors were all in good condition, it said.
Heavily armed pirates using speedboats operate in and around the Gulf of Aden where they prey on ships, sometimes holding vessels for weeks before releasing them for large ransoms paid by governments or ship owners.
The Chinese navy participates in an international anti-piracy force in the area.
In November, a Singapore-flagged cargo ship with 19 Chinese crew that had been hijacked by pirates off the coast of Somalia five months before was freed after sources said a ransom of several million dollars was paid.
Noel Choong, head of the International Maritime Bureau's piracy reporting centre, in Kuala Lumpur, said atta