The U.N. humanitarian chief bluntly told the Security Council on Friday that its recent appeal for humanitarian access in Syria has made little difference and implored the world body to exert more pressure on the warring parties to allow the delivery of aid to millions of people trapped in the conflict.

The message from Valerie Amos further laid bare how ineffective the Security Council has been in addressing Syria's 2 ½-year-old civil war amid divisions between the United States and other Western powers, which support some of the rebel groups, and Russia, which supports the regime of President Bashar Assad.

Diplomats had characterized the humanitarian appeal three weeks ago as a hopeful step toward overcoming the paralysis. It came immediately after the council's first binding resolution on Syria that ordered the elimination of its chemical weapons.