Washington (CNN) -- The Syrian regime this week fired at least two Iranian-made, short-range ballistic missiles in what appears to be an effort to more precisely target Syrian rebels, two U.S. military officials tell CNN.
The Fateh A-110 missiles are more accurate than the older Scud variants that Syrian government forces have used in recent weeks.
The U.S. military officials declined to be identified because of the sensitive nature of the information. The Iranian government has not commented on the issue.
The Fateh trades range for accuracy. It can travel about 125 miles, while the Scud can go about 185 miles. But the Fateh has a "circular error probable" or -- CEP -- of 330 feet, while the Scud's CEP is 1,480 feet. CEP is defined as the radius of a circle in which half of a missile's lethal payload falls and is the standard measure of a missile's accuracy.
The firings did not reach near Syria's Turkish border. But the regime's use of ballistic missiles is the reason NATO is planning to send U.S., German and Dutch Patriot missile batteries to Turkish military installations: to protect the southern regions of that NATO ally. All six Patriot batteries are expected to be in place by the end of January.
A NATO official could not confirm the use of short-range ballistic missiles this week, but NATO did detect the launch of such missiles inside Syria on a few December days, more recently on the 22nd.
"The fact that Scud-type missiles were used in Syria emphasizes the need for effective defense protection of our ally Turkey," the NATO official said. "This is why, earlier this month, NATO allies decided to deploy Patriot missiles in Turkey to augment Turkey's air defenses. The deployment, which will start within weeks, is defensive only. Its aim is to deter any threats to and defend and protect the population and territory of Turkey."
U.S. officials say they believe the Syrians are firing ballistic missiles to preserve their aircraft, some of which have been shot down by rebels.