In this Aug 4, 2016 file photo, people gather to take basic food stuffs and other aid from community leaders charged with distributing equitably the supplies to the 64,000-person refugee camp called Ruqban on the Jordan-Syria border. (AP Photo)

UNITED NATIONS – A UN Security Council mandate for UN aid deliveries to some 4 million people in Syria from Turkey expired on Sunday as diplomats struggled to find a deal with Russia, which traded barbs with the United States over the renewal of the operation.

Russia vetoed a one-year extension on Friday and then failed in its own push for a six-month renewal. The US, Britain and France have said a six-month extension is not long enough for aid groups to plan and operate effectively.

Ireland and Norway are still working to reach a compromise, diplomats said, but a vote on Sunday was unlikely so the huge UN aid operation would be shut down. In 2020 the mandate ran out, but was renewed a day later on the council's fifth attempt.

UN aid chief Martin Griffiths told Canada's CBC television on Sunday that the operation, which delivers aid including food, medicine and shelter, was a lifeline and that if it cannot continue "people will die."

READ MORE: UN Security Council feuds over how long to extend Syria aid

Russia vetoed a one-year extension on Friday and then failed in its own push for a six-month renewal, which would have required the 15-member body to adopt a new resolution in January to extend it for another six months.

The United States, Britain and France have said a six-month extension is not long enough for aid groups to plan and operate effectively.

US Ambassador to the United Nations, Linda Thomas-Greenfield, spoke to aid groups on Sunday, who told her that without the UN operation 70% of food needs would go unmet."

"An entire generation is at risk," she posted on Twitter. "The NGOs (aid groups) asked the UNSC to continue fighting to save these lives ... We have been working all weekend with the UNSC to find compromise."

Russia's Deputy UN Ambassador Dmitry Polyanskiy replied on Twitter: "There's no need to fight and you know it perfectly well!" He said Russia was not trying to kill the UN operation and just wanted to make it more efficient and transparent.

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After the two council votes on Friday, Polyanskiy said that Moscow would continue to veto any text other than its own.

Russia argues that the UN aid operation violates Syria's sovereignty and territorial integrity. It says more aid should be delivered from inside the country, raising opposition fears that food and other aid would fall under government control.

The Security Council vote on the authorization of the aid operation has long been a contentious issue, but this year also comes amid heightened tensions between Russia and Western powers over Moscow's Feb 24 invasion of Ukraine.

In 2014, the Security Council authorized humanitarian aid deliveries into opposition-held areas of Syria from Iraq, Jordan and two points in Turkey. But veto powers Russia and China have whittled that down to just one Turkish border point.

READ MORE: UN chief says 11 years of 'brutal fighting' in Syria must end