China sent three navy ships to the Gulf of Aden to protect shipping
Ships from two navies in the Gulf of Aden have thwarted separate pirate attacks on two merchant vessels.
A Chinese navy helicopter drove off a number of small pirate boats closing in on an Italian-owned ship, China's state-run Xinhua news agency reports.
And a Danish warship answered an alert from a Chinese cargo ship under attack and seized a pirate skiff and weapons, the US navy says.
There has been a surge in pirate attacks off Somalia this year.
A helicopter from one of the Chinese vessels spotted pirates close to the cargo ship and fired flares to warn them off, Xinhua said.
China sent three ships to help patrol the Gulf of Aden - a crucial shipping lane connecting Europe and Asia - late last year.
It is the second successful rescue for the squadron. In January, a Chinese destroyer saved a Greek ship from attack.
In the other rescue, the Danish ship, the Absalon, "closed on the co-ordinates given by the Chinese ship following their distress call and spotted a skiff matching the description given by the captain of the motor vessel", a statement from the US Naval Forces Central Command, based in Bahrain, said.
The crew on the Chinese ship, MV Yandanghai, had prevented the pirates from boarding by taking evasive manoeuvres and training their fire hoses on their skiff.
When the Danes arrived, they boarded the skiff and found several weapons, including a rocket-propelled grenade (RPG), four AK-47 assault rifles, two grenades and a knife, the US navy said.
Two of the Yandanghai's crew were reported to be lightly injured in the attack.
The International Maritime Bureau's piracy reporting centre says that 2008 saw a record number of pirate attacks globally.
The waters off Somalia accounted for nearly 40% of the 293 attacks reported.
Vessels seized included a Saudi oil tanker and a Ukrainian ship transporting weapons, including tanks.
Both were released after ransoms were paid.
The attacks have continued this year. On Sunday the Greek-owned cargo ship MV Saldanha was seized by pirates in the Gulf of Aden.
Warships from more than a dozen nations, including the UK, the US, France, Germany and Iran are now patrolling the Gulf of Aden in an attempt to deter the pirates.