Turkey made its request for Patriot missiles to combat the potential threat of both ballistic and chemical missiles from Syria, according to an unnamed NATO diplomat.
The United States yesterday issued a stern warning following reports that Syria's chemical weapons had been moved and could be prepared for use in response to dramatic gains by rebels fighting to topple President Assad.
Syria later denied it would use chemical weapons against its own people.
Yet the NATO diplomat, speaking on condition of anonymity, confirmed Turkey was fearful of a potential chemical threat, saying:
Turkey's request, when it came to Patriots, was to augment its air defences with the capacity to deal with the threat of ballistic missiles and particularly the threat of ballistic missiles potentially armed with chemical warheads.
General Richard Myers has told ITV News that the real threat in Syria is from Islamist groups using chemical weapons - not President Assad.
NATO agrees to deploys Patriot missiles along the Syria/Turkey border but denies claims that it is taking an active role in the conflict.