"Obviously is is a serious fact - it is not worth playing this fact down," Azeredo Lopes told journalists in Brussels, where he was attending a North Atlantic Treaty Organisation ministerial meeting. "It is always serious when military premises are the target of criminal actions involving the theft precisely of military material."

This was especially true given that “not one pistol was stolen, not two, but grenades were stolen," the minister said, adding that "obviously" Portugal would inform its allies of what had happened.

Now, he said, “the question has been put immediately under the military police and the Polícia Judiciária", Portugal's main criminal investigation force, while military chiefs are to discuss the matter of the security of military material.

Sources earlier told Lusa that "about 50" grenades were found to missing on Wednesday from the weapons store in in Tancos, central Portugal, after a routine patrol of the base there found that the store had been broken into.