Madrid  - A Spanish judge has released one of two suspected Somali pirates brought to Spain after he turned out to be a minor, judicial sources said Tuesday.

Judge Santiago Pedraz ordered the release of the suspect after several medical investigations showed him to be 17 years old, the sources said.

The pair were suspected of participating in the hijacking of Spanish fishing vessel MS Alakrana on October 2. The vessel is currently being held off Somalia while Spanish negotiators are trying to obtain the release of its 36-member crew.

Two of the 13 suspected pirates were detained by a Spanish frigate participating in the European Union's anti-piracy Operation Atalanta when they left the Alakrana on board a skiff two days after the hijacking.

The two were brought to Spain, where they were interrogated by investigating Judge Baltasar Garzon. They said they were only fishermen whom the pirates paid for towing their vessels.

The pirates set the release of their two comrades as one of the conditions for freeing the fishermen, who include 16 Spaniards, as well as Asians and Africans. (dpa)