UNITED NATIONS, United States (AFP) - The UN Security Council adopted a resolution Monday authorising humanitarian convoys to assist more than one million Syrian civilians in rebel-held areas, without the consent of Damascus.

The council unanimously approved the measure, including permanent members Russia and China, who have vetoed four Western-backed draft resolutions on Syria since the start of the conflict in 2011.

The shipments will travel through four different border crossings - two in Turkey (Bab a-Salam and Bab al-Hawa), one in Iraq (Al-Yarubiyah) and another in Jordan (Al-Ramtha). All three neighbouring countries are also hosting large numbers of refugees from the four-year conflict.

The resolution will allow immediate aid deliveries to 1.3 million civilians in rebel-held areas, British Ambassador Mark Lyall Grant told the Council.

"It marks a major step forward in the international community's effort to respond to the suffering in Syria," he said.

More than 10.8 million Syrians are in need of aid, according to UN officials, who have accused Damascus of impeding deliveries of life-saving supplies.

British Foreign Secretary William Hague said the resolution would put an end to President Bashar al-Assad's "stranglehold" on aid routes.

"Many vulnerable communities remain completely besieged because of the regime's starve or surrender tactics. So this process of cross-border aid delivery must start without delay," said Hague.

The draft resolution had been the focus of tough negotiations for five weeks, with Moscow insisting that the Syrian regime be given some rights to monitor the convoy movements.

The authorisation is valid for 180 days and must be renewed by the council.