The UN has sent its first humanitarian aid convoy into rebel-held areas of Syria without government consent on Thursday, as UN chief Ban Ki-moon accused warring parties of denying assistance to millions as a tactic of war.

"A convoy of nine trucks crossed into Syria today from the Turkish crossing at Bab al-Salam, carrying UN food, shelter, water purification and sanitation supplies," said Amanda Pitt, the spokeswoman for UNOCHA, the UN humanitarian office.

The UN Security Council unanimously adopted a resolution 10 days ago that authorised aid access at four border crossings from Turkey, Iraq and Jordan, even though the Syrian government deems such deliveries as incursions.

No further details were available on whether the trucks had reached the people it was intended for.

In a report to the Security Council, obtained by Reuters on Thursday, Ban said that an estimated 10.8 million people need help, of which 4.7 million are in remote areas of Syria.

'Obstructing humanitarian aid'

"The parties have continued to obstruct humanitarian assistance to those most in need and to withhold consent for operations in a completely arbitrary manner as a tactic of war," Ban said in the report, dated Wednesday.

Ban has reported monthly to the Security Council on the implementation of a resolution adopted in February demanding rapid, safe and unhindered aid access in Syria. The United Nations says that resolution had failed to make a difference and that the humanitarian situation on the ground had worsened.

The action then taken by the council on July 14 was a follow-up to the February resolution. The new resolution threatens "further measures in the event of non-compliance". The council would need a second resolution to impose punishments.

The new resolution allows aid deliveries across Al Yarubiyah on the Iraq border, Al-Ramtha from Jordan and Bab al-Salam and Bab al-Hawa from Turkey and established a monitoring mechanism for loading aid convoys in those countries, which will notify Syria of the "humanitarian nature of these relief consignments."