The United States has decided to allow airstrikes to defend Syrian rebels trained by the US military from any attackers, even if the enemies hail from forces loyal to Syrian President Bashar Assad, US officials said on Sunday.
The decision by President Barack Obama, which could deepen the US role in Syria's conflict, aims to shield a still-fledging group of Syrian fighters armed and trained by the United States to battle Islamic State militants -- not forces loyal to Assad.
But in Syria's messy civil war, Islamic State is only one of the threats to the US recruits. The first batch of US-trained forces deployed to northern Syria came under fire on Friday from other militants, triggering the first known US airstrikes to support them.
US officials, speaking on condition of anonymity to confirm details of the decision, first reported by the Wall Street Journal, said the United States would provide offensive strikes to support advances against Islamic State targets.
The United States would also provide defensive support to repel any attackers.
US officials have long played down the idea that Assad's forces - which have not fired on US-led coalition aircraft bombing Islamic State targets in Syria - would turn their sights on the US-backed Syrian rebels. But they cannot rule out the possibility, perhaps in an unintentional clash.
The Pentagon and the White House declined to discuss the decision on rules of engagement or confirm comments by the unnamed US officials.