[AP]

FILE - This undated file image posted on a militant website on Tuesday, Jan. 14, 2014 shows fighters from the al-Qaida linked Islamic State of Iraq and the Levant (ISIL) marching in Raqqa, Syria. Historically, Raqqa and Mosul and the surrounding areas that make up Northern Mesopotamia _ a region known as the Jazira _ have had more in common with each other than they did with distant Southern Mesopotamia centered on Baghdad and Basra. The desert wadi routes that the Islamic State uses to smuggle its weapons, fighters and money back and forth across the border are the same trade routes established five millennia ago when the first cities arose in the Upper Tigris and Euphrates valleys. (AP Photo/Militant Website, File)