The White House is mulling a major shift in policy on war-torn Syria and could supply rebels with "non-lethal" aid such as body armour, armoured vehicles and perhaps even military training, according to a newspaper report.

Citing unidentified US and European officials, the Washington Post also reported that Washington could send humanitarian aid directly to the country's opposition political coalition.

The Post, while noting that US officials remain opposed to providing arms to the rebels, said US secretary of state John Kerry was discussing yet to be finalised elements of the "proposed policy" in meetings with allies.