The Antigua and Barbuda-flagged, Slovenian-owned Ariella sent a distress call in the early hours of the morning when it was boarded by pirates in the Gulf of Aden.

An Indian warship picked up the distress signal, then Danish warship Absalon, operating under NATO command, responded to the call once a French helicopter had established that pirates were on deck.

The crew had locked themselves in a secure room ... once the special forces knew they were secure, they stormed the ship and the pirates fled, John Harbour, spokesman for the European Unions anti- piracy mission off Somalia (EU NAVFOR) told the German Press Agency dpa.

The crew - 15 Filipinos, seven Ukrainians, one Slovak, one Indian and one Bulgarian - were all safely rescued.

Harbour said the special forces were in control of the ship, and that the pirates fled in advance of the attack.

They (the pirates) could still be on the ship or may have gone overboard in a skiff, he said.

EU NAVFOR said in a statement that Russian Navy ship Neustrashimyy, operating nearby, boarded and detained a second pirate skiff.

Piracy is rife off the Horn of Africa nation, which has not had an functioning central government since 1991.

Young men take to the seas in search of multimillion-dollar ransoms despite the presence of over a dozen international warships, which were dispatched to the Gulf of Aden in 2008 to combat a rise in piracy.

The pirates have expanded their operations further out into the Indian Ocean to avoid the patrols.

Harbour said the rescue was possible because the ship was registered with the naval force and was travelling in a convoy along an agreed transit corridor, allowing a fast response.

The Absalon has already played a significant role in fighting piracy in the region.

A year ago the crew of the Absalon rrested five Somali pirates who seized a Dutch ship and last weekend, after arriving for a new tour of duty, helped the crew of an Indian vessel in the Gulf of Aden.

According to the International Maritime Bureau, Somalis were largely responsible for a global increase in pirate attacks in 2009.

There were 406 attacks in 2009, compared to 293 the previous year, and over half of them were off the coast of Somalia, the IMB said.

Somali pirates in January scooped their biggest payday, when a Greek supertanker carrying millions of barrels of crude oil from Saudi Arabia to the United States was released for a ransom rumoured to have been as high as 7 million dollars.