According to BBC News
Turkey has sent these jets near the country's volatile border with Syria in response to Syrian helicopters commencing operations near the border. 30,000 Syrian civilians fled over this border into Turkish refuge camps due to the violence of the 16-month-long uprising there.
The helicopters in question where a mere 4 miles from crossing the border into Syria. The F-16's are presently at the ready to scramble and intercept any helicopters that may stray across the border and shoot them down if necessary.
Since the deployment four jets have been scrambled from Incirlik Air Base as Syrian helicopters flew close to the Turkish Hatay Province. Following that two F-16's took off from their Turkish base near the city of Batman in southeastern Turkey in response to Syrian helicopters operating near the province of Mardin.
There has been rising tensions between the two countries since the conflict began, these tensions have increased substantially following the shooting down of a Turkish Air Force F-4 Phantom II jet fighter by Syria's air defence. Syria and Turkey still dispute the finer points of whether or not that jet was downed over Syrian territorial waters or over international waters. Turkey has however conceded that the jet briefly did incur Syrian airspace by accident but quickly pulled out.
This latest deployment of F-16's comes after the recent deployment of anti-aircraft weaponry
along the border. Turkish Prime Minister Recep Tayyip Erdogan has warned that any Syrian military unit approaching its border would be considered a military threat to Turkey.
Erdogan has recently described Syria as a "clear and present threat."