UNITED NATIONS (Reuters) - Russia said on Friday that a U.N. Security Council endorsement of a Syria ceasefire deal between Moscow and Washington appeared unlikely because the United States does not want to share the documents detailing the agreement with the 15-member body.

Smoke rises over a damaged site as Civil Defence members try to put out a fire after an airstrike on al-Jalaa street in the rebel held city of Idlib, Syria. REUTERS/Ammar Abdullah

Russian U.N. Ambassador Vitaly Churkin and U.S. Ambassador Samantha Power had been due to brief the council behind closed-doors on Friday but that was canceled at the last minute.

“The main problem ... which in my mind makes it impossible to produce any resolution, is that they are refusing to give those documents to members of the Security Council or even to read those documents to the members of the Security Council,” Churkin told reporters.

“We believe that we cannot ask them (council members) to support documents which they haven’t seen,” said Churkin, suggesting there was lack of unity in U.S. President Barack Obama’s administration toward the agreement.

The U.S. mission to the United Nations said it could not agree with Russia on a way to brief the council that would “not compromise the operational security of the arrangement.”

“Right now we are focused on the implementation of the agreement brokered by Secretary Kerry and Foreign Minister Lavrov, particularly the urgent need for humanitarian aid to reach Syrians in need,” a U.S. spokesperson said in a statement.

The deal reached on Saturday aims to put Syria’s peace process back on track. It includes a nationwide truce that started at sundown on Monday, improved humanitarian aid access and joint military targeting of banned Islamist groups.

Russian Foreign Minister Sergei Lavrov and U.S. Secretary of State John Kerry reached agreement on five documents, which they said would not be publicly released. However, France on Thursday called on the United States to share details of the deal.

Churkin said Russia has given two drafts of a possible Security Council resolution to the United States. He said on Thursday that Moscow hoped a resolution could be adopted next week during the annual U.N. gathering of world leaders.

“They, in their typical way, came up with a completely different thing, which is trying to interpret and reinterpret the agreement,” Churkin said, referring to U.S. officials.

A Security Council endorsement would add political weight to the deal, but would have no implications on the ground.

The United States and Russia said on Friday they wanted to extend the four-day-old ceasefire in Syria that they have co-sponsored, although the agreement looked increasingly shaky, undermined by increasing violence and a failure to deliver aid.