Russia's U.N. envoy clashed with the world body's humanitarian chief as well as U.S. and other Western diplomats on Wednesday over extending the delivery of humanitarian aid across borders and conflict lines in Syria which has helped thousands of people in rebel-held areas.

Russian Ambassador Vassily Nebenzia told the U.N. Security Council that the current resolution authorizing cross-border convoys "cannot remain as it presently stands."

"This undermines sovereignty of Syria," he said of the mandate, which is to expire in December. "It was ... an emergency measure which presently needs to be reassessed."

The Security Council has authorized cross-border aid deliveries since 2014.

U.N. humanitarian chief Mark Lowcock told council members that Secretary-General Antonio Guterres has called for the mandate's renewal, saying it is "essential to save lives."

In the first 10 months of 2017, he said, "over 750,000 people on average each month were reached through U.N. cross-border activities."

U.S. Deputy Ambassador Michele Sison told the council it must renew the authorization for cross-border deliveries.

"The consequences of this mandate are enormous," she said. "It's not an exaggeration to say that renewing this mandate is a life or death question."

Sweden's deputy ambassador, Carl Skau, stressed that the needs in Syria remain tremendous and said his government would start discussions on a new resolution to renew the mandate with members, calling the council meeting "a kickoff."

Lowcock told the council that trucks crossing the border at Bab al-Haqa, Bab as-Salam and Al-Ramtha are checked by U.N. monitors to ensure they contain only humanitarian supplies.

He said deliveries are then confirmed by U.N.-contracted third party monitors when they arrive at warehouses inside Syria. There is then post-distribution monitoring by independent third parties.

Nebenzia said that "this is not sufficient for us" and Russia will request a closed Security Council briefing next week on cross-border provisions.

He noted that "positive changes on the situation on the ground" thanks to cease-fire arrangements reached by Russia, Syria and Turkey in Syria have helped increase the volume of convoys through government checkpoints.

"We are encouraging the Syrian authorities to engage constructively," Nebenzia said. "At the same time there needs to be order in the distribution of humanitarian assistance for it not to fall into the hands of terrorists and for it not to then be resold to the Syrian people at higher prices."

Lowcock told the council that assistance to areas under government control represents the majority of U.N. deliveries, with 2.8 million people in those areas receiving food in October.

By contrast, he said, convoys crossing conflict lines "continue to be heavily restricted," with only four getting through in November and reaching just 228,000 people.

News from © The Associated Press, 2017