The Obama administration has decided to provide air cover to the Syrian rebels it has trained if they come under attack by the Assad regime, potentially deepening the US role in the four-year old Syrian conflict.
The Syrian fighters are being trained by the US to take on Islamist militants from Isis but there is also a chance that they could also come under attack from Assad regime forces.
The administration has been reluctant to discuss any military action against the Assad regime for fear that it could lead to greater US involvement in the civil war, but felt it was necessary to provide greater assurances to the fledgling rebel force it has been building up.