A Portuguese warship seized explosives from suspected Somali pirates after thwarting an attack on a Norwegian oil tanker, a NATO spokesman said Saturday. It was the first time NATO forces found pirates armed with raw explosives, Lt-Cmdr. Alexandre Santos Fernandes said from the Portuguese frigate the Corte-Real. The four sticks of P4A dynamite _ which could be used for demolition and blasting through walls _ were destroyed along with four automatic rifles and nine rocket-propelled grenades also confiscated. It was unclear how the pirates planned to use the dynamite, Fernandes was quoted as saying by Associated Press. The Corte-Real had sent a helicopter to investigate a distress call from the Norwegian-owned MV Kition late Friday about 100 miles (161 kilometers) north from the Somali coast in the Gulf of Aden. The suspects fled to a larger pirate vessel, but were intercepted by the warship an hour later. «The skiff had returned to the mothership,» Fernandes said. «Portuguese special forces performed the boarding with no exchange of fire.» The 19 pirate suspects were released, however, after consultation with Portuguese authorities because they had not attacked Portuguese property or citizens. Fernandes said Portugal was working on updating its laws to allow for pirate suspects to be detained in such situations. Nearly 100 ships have been attacked this year by pirates operating from the lawless Somali coastline despite the deployment of warships from over a dozen countries to protect the vital Gulf of Aden shipping route.