DEBKAfile’s military sources disclose that the Islamic State took advantage of the Syrian-Hizballah-Shiite militias’ preoccupation with seizing the Syrian-Iraqi border to launch a large-scale surprise attack Thursday on the big Syrian air base at Deir ez-Zor. This is the second ISIS attack on the eastern Syrian town in the last 48 hours. This time, the jihadists formed a wedge between the air base and the town and forced the Syrian defenders, the 137th Brigade, to retreat.