Two aid convoys destined for Syria's Aleppo, with enough supplies to feed 185,000 people for a month, remained stuck in Turkey on Monday as rebels said a landmark ceasefire had effectively ended.
The UN has said it does not have sufficient security guarantees from all sides in the conflict, now in its sixth year, to be able to deliver the 40 trucks of aid to eastern Aleppo, which is held by rebels battling to topple President Bashar al-Assad.
The aid has been sitting at the border for nearly a week, as the patchy seven-day ceasefire was punctuated by fighting and air raids, with all sides accusing each other of violating it.
The UN also wants to deliver aid to other hard-to-reach parts of the country, but says it has not received the necessary permissions from the government to proceed.
A rebel official told the Reuters news agency that truce, brokered by the US and Russia, had ended, and there was no hope the eastern Aleppo aid would be delivered.
According to a timetable set by Moscow and Washington, the ceasefire was due to officially expire at 1600 GMT on Monday. The Syrian army, though, said last week it would expire at midnight on Sunday.
Up to 275,000 people remain trapped in eastern Aleppo - Syria's most populous city - without food, water, proper shelter or medical care, said UN Under Secretary General for Humanitarian Affairs Stephen O'Brien.
READ MORE: US air raid on 'Syrian army post' sparks Russia tension
"I am pained and disappointed that a United Nations convoy has yet to cross into Syria from Turkey, and safely reach eastern Aleppo," O'Brien said in a statement, referring to a 20-truck convoy, the first of two that would have carried flour and other food supplies.
Both convoys were still sitting at the Turkey-Syria border, where they have been for almost a week, UN spokesman Jens Laerke said.
Humanitarian access to Aleppo hinges on control of the main road into the besieged rebel-held part of the city.
The road needs to become a demilitarised zone in order for aid to proceed. Russia said the Syrian army had begun to withdraw from the road, but rebel groups in Aleppo have said they have seen no such move and would not pull back from their own positions around the road until they did so.
"I hope that all parties to the conflict, and those with influence over them, would see the convoy as an opportunity to move forward," O'Brien said.
"Humanitarian aid must remain neutral, impartial and free of political and military agendas."
A senior Syrian opposition figure said on Monday that the ceasefire was "clinically dead".
George Sabra of the High Negotiations Committee (HNC) told The Associated Press news agency that the truce had been repeatedly violated and did not succeed in opening roads for aid to enter besieged rebel-held areas.
On Monday, the opposition reported 254 violations by government forces and their allies since the truce started on Sept. 12. Syrian state media said there were 32 violations by rebels on Sunday alone.
Syrian state news agency SANA reported last last week that the truce would last until midnight on Sunday. There has been no announcement of an extension of the truce.
Source: News Agencies