Bashar al-Assad is becoming an increasingly lonely dictator. Reports from neighboring Turkey said more Syrian military officers defected across the border Monday, raising tensions in the two countries. Turkey is already at odds with its neighbor over Syria’s decision to shoot down a Turkish fighter jet Friday—a response that Syria claims was automatic after the plane entered Syrian airspace. As Turkey, a NATO member, has contemplated its options over the weekend, European leaders have urged caution. “We will obviously be looking to Turkey to be restrained in its response,” European Union foreign-policy head Catherine Ashton told reporters. A general, two colonels, and other Syrian military members crossed the border into Turkey on Monday.