U.N. Chief Ban Ki-moon on Thursday urged the Security Council to consider what action it should take to force compliance with its demands that millions of besieged syrians who have been denied emergency relief get access to much-needed humanitarian aid.

"Despite the clearly expressed will of the council and the best efforts of humanitarian actors, resolution 2139 has yet to make a meaningful difference to the lives of the millions of people in need in syria," Ban said in a report to the council.