A military source told me that Turkey is preparing to put its troops into northern Iraq.
The risks of a clash with the Kurdish military - Peshmergas - is very high indeed. The Kurdish administration which runs northern Iraq has vowed to resist Turkish troops.
The US will now need to referee between the two groups which hold very little regard for each other.
This is a high risk of a clash and of a regional sub-war which would be incredibly messy and very difficult to clear up.