"The Syrian government will not change position even if there is World War III. No Syrian can sacrifice the independence of his country," he said.
"Syria has taken every measure to retaliate against... an aggression," he added, refusing to provide any clue as to what that might mean.
Muqdad said the regime was mobilising its allies ahead of a possible strike, as US President Barack Obama lobbies Congress to back intervention and the French parliament debates the issue.
Washington says the alleged chemical weapons attack on August 21 in suburbs of Damascus killed more than 1,400 people and blames it on the Assad regime – a claim it categorically denies.