People raise the roof of a destroyed building to search for survivors after an air strike in the Duma neighborhood of Damascus on Monday. A UN report says the number of people displaced from their homes within the country has risen to 6.5 million. Bassam Khabieh / Reuters

The United Nations estimates that about 9.3 million people in Syria, or 40 percent of the population, need humanitarian assistance due to the country's two and a half years of civil war, the UN humanitarian office said on Monday.

"The humanitarian situation in Syria continues to deteriorate rapidly and inexorably," UN humanitarian chief Valerie Amos told the UN Security Council behind closed doors, according to her spokeswoman Amanda Pitt.

"The number of people we estimate to be in need of humanitarian assistance in Syria has now risen to some 9.3 million," Pitt said, summarizing Amos' remarks to the 15-nation council. "Of them, 6.5 million people are displaced from their homes within the country."

The population of Syria is roughly 23 million.

"Amos continues to press the council for their help and influence over those parties who can ensure the protection of civilians and civilian facilities, the safe passage of medical personnel and supplies, the safe and unhindered delivery of humanitarian assistance, and can facilitate progress in expanding critical, life-saving relief operations," Pitt said.

Amos' plea to the council follows the Syrian government's promise on Monday to ensure delivery of vaccinations and humanitarian aid across the country, after an outbreak of polio in the northeast and warnings of malnutrition in areas under military siege.

Twenty-two children in Deir al-Zor province bordering Iraq were left paralyzed last month. The polio virus has been confirmed so far in 10 of them, and experts say it could spread quickly across the region.

Last month Amos demanded stronger action by the Security Council to get desperately needed aid into Syria, where millions of people in need have not received any help for almost a year.

Violence and excessive red tape have slowed aid delivery to a trickle in Syria. More than 100,000 people have been killed in the civil war and millions have fled the country. After months of talks, the 15-member Security Council approved a non-binding statement on Oct 2 urging increased humanitarian access.

Reuters