In the shadow of the announced and started offensive on Raqqa, as well as the near complete defeat of the Northern Aleppo rebels by IS, the SDF started an attack on Manbij, and possibly Jarabulus. On June 1st the Manbij Military Council officially declared the offensive.
The bridgehead near the Tishrin dam has been held for a rather long time. SDF now finally started to expand the exposed salient to all sides. Especially the right side of the Euphrates is starting to get cleared. This is an operation from two sides. On one hand the SDF is attack from Tishrin dam bridgehead, on the other hand they crossed the Euphrates near Qarah Qazwag via the repaired bridge as well as by boat. The attack on Manbij will probably be three-pronged from the North, East and South pushing IS in front of them to the west.
The offensive is going extremely fast. Vast gains have been made in these two days. It is obvious that IS is stretched pretty thin in Syria between their Northern Aleppo offensive, the defense in Raqqa countryside and now the Manbij offensive. In Iraq they have to defend their heartland from the offensive for Fallujah. Reportedly today the SAA and their allies started an offensive to capture Al Tabqah, and further on Raqqa. Pressure is mounting from all sides on IS.
What happened that finally made the Manbij offensive possible? Turkish objections over the SDF connecting the Cantons have silenced. With the failure of the Turkish backed Northern Aleppo rebels, who would have created Turkeys long desired safe zone, the USA probably lost their patience. In retrospective the USA gave Turkey a chance to fight IS in their own way. When this didn’t work out, the USA turned back to the SDF, gave them the green light and the guarantee to stop Turkey from objecting. Attacking Raqqa could very well be the price SDF is paying for US support.
Personally I doubt that Raqqa will fall soon or easily, nether to the SDF and the USA nor to the SAA and Russia. But once the border to Turkey is sealed their main smuggling route for supplies will be cut off. This would hurt them strongly, as only the Syrian and Iraqi black market would remain, as well as battlefield captures.
— diyar Ciwan (@ciwan124) 2. Juni 2016