NATO missile defense for Turkey-Syria border?

Turkey and NATO set to begin reviewing possible sites for air defense missiles Turkish military: A missile defense system would be used only defensively Dissidents say regime forces are dropping barrel bombs in Aleppo province At least 168 people were killed across Syria on Monday, an opposition group says

(CNN) -- A NATO reconnaissance team is expected to survey the Turkish-Syrian border on Tuesday to prepare for the possible deployment of Patriot anti-aircraft missile batteries along the frontier.

Turkey has turned against its former ally, asking its fellow NATO members last week for Patriot missiles to bolster its air defenses because of several Turkish deaths blamed on Syrian forces.

A delegation of Turkish and NATO officials is scheduled to begin a site survey Tuesday to determine where to deploy the batteries, the Turkish military said Monday.

"The deployment of the Air and Missile Defense System is a precaution for defensive purposes for possible air and missile threats from Syria, and is not for the establishment of a no fly zone or for offensive maneuvers," according to a Turkish military statement.

"The area of deployment for the Air and Missile Defense System, the quantity of the system, the number of foreign personnel that will come in to our country and the time of the deployment will be determined after the site survey."

The fact that Syrian warplanes and helicopters have bombed targets within a few hundred meters of Turkey at least three times in the past month raises the question of whether the NATO military alliance could be sucked into the grinding Syrian civil war.

Tensions exploded between Syria and Turkey last summer, when Syrian anti-aircraft fire brought down a Turkish military reconnaissance jet, killing its two crew members.

Turkey announced it was changing its rules of engagement with Syria. In October, the Turkish government won authorization in parliament for possible cross-border military incursions into Syria after Syrian mortar fire killed five civilians in the Turkish border town of Akcakale.

The Turkish military has scrambled warplanes to the border before in response to Syrian aircraft approaching Turkish airspace. Turkish and Syrian military forces have also engaged in cross-border artillery duels since the Akcakale incident.

Bloodshed from the Syrian civil war has also seeped into Lebanon, where clashes between pro- and anti-Syrian factions have turned deadly.

And Israel's army fired warning shots toward Syria this month after a mortar shell hit one of its military posts.

On the ground in Syria, "fierce aerial shelling" bombarded parts of northwest Syria on Tuesday, dissidents said. The opposition Local Coordination Committees of Syria said regime forces dropped more than 10 barrel bombs on the Aleppo province city of Deir Hafer.

The latest reports of violence came a day after 168 people were killed across the country on Monday, the LCC said.

About 40,000 civilians have been killed since the first protests sprung up 20 months ago against al-Assad's government, according to the opposition Center for Documentation of Violations in Syria. And more than 380,000 Syrian refugees have fled to neighboring countries such as Turkey and Lebanon, creating humanitarian challenges abroad.

The Syrian government routinely refers to its battle against "terrorists," the term it uses for rebel fighters and extremist elements in the country.

CNN cannot confirm claims by the government or the opposition because of government restrictions that prevent journalists from reporting freely within Syria.

What started as security forces cracking down on mostly nonviolent protesters has spiraled into a civil war between pro-government forces and the rebels, including the Free Syrian Army.