Is this the tomb of Sultan Suleiman the Magnificent, who ruled the Ottoman Empire at its zenith?
If so, it is a holy site for all Turks, and they will attack ISIS with their own brand of savagery, demonstrated as recently as 1915.
"The Tomb of Suleyman Shah (Turkish: Süleyman Şah Türbesi) is a sovereign exclave of Turkey situated in Aleppo, Syria. It is the burial place of Suleyman Shah, the grandfather of Osman I, the founder of the Ottoman Empire."
First time I ever ran into the word "exclave," by the way.