In what some defense analysts are calling a serious escalation of the Syrian civil war, Syria's air force bombed Kurdish units with embedded American advisors. The US scrambled its own jets to chase the Syrian planes away but that didn't stop them from hitting the Kurds anyway.

Daily Mail:

Syrian regime jets pounded US-backed Kurdish forces in northeastern Syria for a second day, even after the US-led coalition scrambled jets to protect its military advisers working on the ground.

In another escalation of Syria's bloody conflict, warplanes from President Bashar al-Assad's regime were bombarding the city of Hasakeh -- targeting Kurdish forces that for months have worked closely with coalition military advisers helping local fighters combat the Islamic State group.

On Thursday, the United States sent fighter jets to head off air strikes conducted by regime planes and to protect coalition advisers, but the Syrian planes had left by the time they arrived.

If Assad has decided to take his chances and accept the possibility of hitting Americans in targeting the Kurds, it will almost certainly lead to conflict with coalition planes.

It was apparently the first time the coalition had scrambled jets in response to a regime action, and possibly the closest call yet in terms of Syrian forces coming close to killing American or coalition advisers.

"This was done as a measure to protect coalition forces," Pentagon spokesman Captain Jeff Davis said.

"We will ensure their safety and the Syrian regime would be well-advised not to do things that place them at risk... We view instances that place the coalition at risk with the utmost seriousness and we do have the inherent right of self-defense."

But the Pentagon warning appeared to fall on deaf ears.

Two Syrian regime warplanes attempted to fly to the area again on Friday, but were met by coalition aircraft, a US defense official said in a statement.

"The presence of the coalition aircraft encouraged the Syrian aircraft to depart the airspace without further incident," he said. "No weapons were fired by the coalition fighters."

Most of Hasakeh city is controlled by Kurdish forces, while the rest is held by fighters loyal to President Bashar al-Assad.

Since Wednesday, clashes between the two forces have rocked the city, leaving 23 civilians -- including nine children -- and 16 combatants dead, according to the Syrian Observatory for Human Rights.

Davis said no coalition injuries were reported in Thursday's strike by two Syrian SU-24s, and US special operations advisers have been moved to a safe location.

What does Assad hope to gain by threatening Americans? It's a safe bet that President Obama would pull any forces we have embedded with the Kurds back from the action if there was a chance there would be American casualties. The fact that special operations forces have moved to a "safe location" confirms that. 

You have to wonder what the Kurds think of their American allies disappearing at the first sign of danger. They must also be frustrated when their American allies have a perfectly good air force that is doing nothing to protect them from either Russia or Syria. Ultimately, Assad may be demonstrating to the Kurds the powerlessness of their American allies.