Islamic State crisis: Turkey reinforces border security
Turkey insists its 900km-long (560 mile) border with Syria is a bulwark against Islamic State (IS) and other jihadist groups.
The Turkish army has been accused of being too lax in protecting the border and is keen to show it is now taking a hard line.
The battle to protect the border from militant groups also means that Syrian refugees fleeing the government of President Bashar al-Assad are also being picked up in the sweep.
The BBC's Mark Lowen reports from the Turkey-Syrian border.