The U.N.'s chief humanitarian official on Thursday asked the Security Council to approve cross-border relief operations into Syria to deliver aid to civilians.

It was the opening of a public briefing by the U.N. agency chiefs for humanitarian affairs, refugees, women in conflict, and children in conflict, who used the Security Council platform as a way of speaking over the heads of the deadlocked council nations to appeal to the world for pressure to allow relief for Syria's civilians.

The agency chiefs launched their campaign Monday with an op-ed in The New York Times that said: "There still seems to be an insufficient sense of urgency among the governments and parties that could put a stop to the cruelty and carnage in Syria."

Undersecretary-General for Humanitarian Affairs Valerie Amos said the U.N. agency is currently hampered by Syria's requirement that two Syrian government ministers must sign approval papers for every truck allowed into the country. She said children are starving to death in Syria for want of food aid.

The Security Council has been deadlocked for months on the Syrian war, and is not expected to act or make any statement after Thursday's briefing.

Western and Arab nations blame the conflict on Syrian President Bashar Assad's government. Russia insists on assigning equal blame for the suffering to the Syrian rebel opposition, and has cast vetoes to block draft council resolutions.

The U.N. High Commissioner for Refugees, António Guterres, thanked Turkey for taking in Syrian refugees, and especially called for international funding for Jordan and Lebanon to help them operate their refugee camps.

More than 5 million people have been displaced by the Syrian conflict, which began over two years ago. In the past few weeks, the humanitarian agencies have separately warned that their resources are running low, and added that without additional funds they will be forced to scale back relief efforts.

Over a million refugees in neighboring countries have been given shelter while U.N. agencies have helped 5.5 million Syrians get access to food, water and sanitation as well as basic health services.

The U.N. special representative of the Secretary-General on Sexual Violence in Conflict, Zainab Bangura, said women in Syria have been "raped, tortured and humiliated."

"Many have attempted to commit suicide," she added.

On Wednesday she presented a report to the council that accused Syria's military and intelligence forces and an allied militia of using systematic sexual violence on women.

She said Thursday that Syria had brought one instance of the rape of a Syrian woman by opposition forces to her attention.

Bangara urged the opposition Free Syrian Army to issue orders to its fighters to respect women and hold rapists accountable, and made the same demand of Syrian government forces and its Shabbiha militia.