"I repeat for the hundredth time that even if such weapons exist in Syria, they will not be used against the Syrian people," Mekdad said. "We cannot possibly commit suicide."
Analysts say the missile deployment sends a message to Assad to keep the war in his own country.
"There is an element there of deterrence, of coercive diplomacy," said Yezid Sayigh of the Carnegie Middle East Center in Beirut. "We won't go further if you don't go further."
Sayigh said it is possible that Syria, too, moved its chemical weapons to send a counter-message to the West.
Still, the missile deployment does not appear to be a step toward military intervention, he said, noting that no NATO member nations want to enter the war.
NATO officials said the Patriots will be programmed only to intercept Syrian weapons that enter Turkish airspace and will not be fired into Turkey preemptively. This means they would not target Syrian military activities that remain inside Syria.
The German Parliament is expected give its final approval in mid-December, and the Dutch are also expected to approve the move soon, allowing the plan to go ahead. Due to the complexity and size of the Patriot batteries, they will probably have to travel by sea and won't arrive in Turkey for another month.
In Syria, government forces shelled rebellious suburbs around the capital, Damascus. They also clashed with rebels in Damascus as well as in the northern city of Aleppo and elsewhere. Anti-regime activists say more than 40,000 have been killed since the country's crisis started with political protests in March 2011.
The fighting in Syria has enflamed tensions in neighboring Lebanon, where security officials said the toll in clashes between two neighborhoods in the northern city of Tripoli had risen to eight dead and more than 60 wounded.
The clashes between the two communities, which support opposite sides in Syria's civil war, started Monday, following reports that 17 Lebanese men were killed after entering Syria to fight alongside the rebels.
The officials spoke on condition of anonymity because they were not authorized to brief the media.
Associated Press writers David Rising in Berlin and Matthew Lee in Washington contributed to this report.