Foreign Minister Antonio Martins da Cruz told state radio that if Portugal were attacked, "it would be unlikely France and Germany would come to our rescue."
His comments to RDP Antena 1 radio were monitored by the British Broadcasting Corp.
He said: "Let us suppose Portugal, proper or its archipelagos, faced a threat, who would come to our rescue? The European Commission, France, Germany?
"I think it would be NATO who would come to our rescue, in other words, it would be the U.S., no one else would defend us. For instance, during the 1996 mission in Bosnia, operations took place with the support of 20 satellites, of which only one was European," and the remainder belonged to the U.S.
"If we were attacked, is that what they would offer to defend us? How curious is this: in Bosnia, when we were called to send soldiers urgently to that region, the U.S. had C-17 and C-130 planes, and France leased ferry boats, which during the summer are employed in tourist services to Corsica.
"Is this how we are supposed to project our forces in Europe? Are they planning to defend us with ferry boats? I cannot envisage the European Commission protecting us from an attack in which highly developed weapons were employed," the foreign minister said.