As neighboring Jordan, Lebanon, Turkey and Iraq struggle to cope with the influx of Syrian refugees that the U.N. refugee agency (UNHCR) said on Friday has surpassed 1.5 million, U.N. officials have told the Security Council there are millions more people in need of aid inside Syria.

But such a battle over a new resolution in the 15-member council, which has long been deadlocked over how to act on Syria's two-year civil war, will likely be left until after a planned Syria peace conference in Geneva next month, U.N. diplomats said.

Russia, a close ally of Syrian President Bashar al-Assad, and China have used their veto power three times to prevent Security Council against Assad that was backed by the remaining three veto powers - the United States, Britain and France.

"The key element (of a humanitarian resolution) would be insisting on cross-border access," said a senior Security Council diplomat, speaking on the condition of anonymity.

"We don't want to open up divisions (between the permanent five council members) ... just before Geneva," he said. "If (the Western council members) are going to have that battle with the Russians then it may be better to have it after Geneva."

Western leaders have been cautious about the prospects of the Syria conference in Geneva achieving any breakthrough, and Russia's desire that Iran should attend has complicated matters.

The Syrian conflict started with mainly peaceful protests against Assad, but turned into a civil war in which the United Nations says at least 70,000 people have been killed. Islamist militants have emerged as the most potent anti-Assad rebels.

Jordan recently invited the Security Council to visit and see first-hand the Syrian refugee crisis it was struggling to deal with, but diplomats said Russia had blocked the trip.

CROSS-BORDER ACCESS QUICKER

John Ging, director of operations for the U.N. Office for the Coordination of Humanitarian Affairs, said the Syrian government had refused to aid access across rebel-controlled borders and that violence, bureaucracy and checkpoints meant aid was barely trickling through to those in need.

"You should have full access by whatever routes, by whatever means are most effective to save the lives of the people who need to be saved," a visibly frustrated Ging told reporters in New York after returning from Syria last month.

"You cannot negotiate 54 checkpoints between Damascus and Aleppo every day with the quantities of aid that Aleppo needs. But you can drive it in the one hour from Turkey pretty efficiently and pretty effectively," he said.

Diplomats said Assad's government's opposition to cross-border humanitarian access in areas controlled by rebels was over concerns that weapons could be smuggled more easily to opposition forces.

U.N. aid chief Valerie Amos painted a dire picture when she briefed the Security Council on April 18 about families burned in their homes, people bombed waiting for bread, children tortured, raped and murdered and cities reduced to rubble.

The bleak assessment motivated the otherwise paralyzed council to reach a agreement on a non-binding statement that demanding an end to the escalating violence and condemning human rights abuses by all sides.

The statement also "underlined the need to facilitate the provision of humanitarian assistance through the most effective ways, including where appropriate across borders in accordance with guiding principles of humanitarian assistance."

The senior U.N. diplomat said that since Russia had agreed to the reference to cross-border aid access in that statement and because Amos had requested the council's help, it would be "quite difficult for the Russians to hold out against it" in a resolution on the humanitarian situation in Syria.

(Editing by Eric Walsh)