GENEVA  - U.N. Syria envoy Staffan de Mistura said on Thursday he hoped the U.N. Security Council would agree a resolution to end fighting in the besieged Syrian enclave of eastern Ghouta, but said it would not be easy.

"I hope it will. But it's uphill. But I hope it will. It is very urgent," he told Reuters as he arrived at the United Nations in Geneva.

Asked what would happen if there were no deal, he said: "Then we will have to push for it to take place as soon as possible because there is no alternative but a ceasefire and humanitarian access."

(Reporting by Tom Miles; Editing by Gareth Jones) ((tom.miles@thomsonreuters.com; +41 58 306 2006; Reuters Messaging: tom.miles.reuters.com@reuters.net))