The US has "accidently" bombed Iraqi government troops when they were advancing against ISIS and the Iranians have asked sarcastically why the US mistakenly drops food and ammunition to areas held by ISIS about 5 times.
But that's nothing, Obama's endgame in Syria has started. If he fails, he will throw in the towel and Assad's regime might survive.
The latest plan is to create a no fly zone/safe zone on the border with Turkey where an elite force of well trained islamist fighters will base themselves and advance against Damascus. When they are engaged, US and Turkish planes will hit the Syrian army to protect them. After the trigger is pulled, this will be a Libya like scenario with a full scale airwar.
BUT... Lavrov and Putin are trying to spoil the party. Deployment of Russian assets was the only way to stop this. Pretty predictable.