The United States and France pushed Tuesday for aid to reach Syria's battlefront city of Aleppo before plans for a new round of talks can move forward.
Russia, however, maintained that there should be no pre-conditions for the talks that the United Nations is hoping to reconvene in Geneva at the end of the month.
US Ambassador Samantha Power told reporters that it was urgent to get peace talks back on track "but the environment for talks also has to be right."
"On humanitarian access, (...) we're in reverse gear," Power said following a closed-door meeting of the Security Council.
Fighting between government forces and rebels in Aleppo has intensified over the past month, with both sides sending in reinforcements for an all-out battle that could mark a turning point in the five-year war.
Up to two million people in Aleppo have gone without running water for the past four days, UN agencies said, raising the risks of disease in a city already devastated by years of fighting.
The council heard a report from UN envoy Staffan de Mistura who said he still hopes to hold the talks at the end of the month but that the humanitarian disaster in Aleppo must be addressed, diplomats said.
"I don't see how we could have meaningful talks if there is not indeed the minimum conducive environment for that," said French Deputy Ambassador Alexis Lamek.
UN aid chief Stephen O'Brien renewed his call for a 48-hour humanitarian truce in Aleppo and said following the meeting that he was "encouraged" that the council appeared to be uniting behind that proposal.
Russian Ambassador Vitaly Churkin said Moscow was in talks with Washington on ensuring deliveries of aid to Aleppo, but rejected suggestions that the peace talks could be derailed over the fighting in the city.
"The lower the level of violence, the better it is for the talks and we share that approach, but there must be no preconditions for the talks," said Churkin.
The ambassador stressed that the major hurdle in the peace process was the opposition's insistence that Syrian leader Bashar Al-Assad must leave power.
"They were coming to the talks without saying anything, you know. They were just saying 'Assad must go' and this is not a negotiating position," said Churkin.
The war in Syria has killed more than 280,000 people and drawn in world powers on both sides since it erupted in March 2011, with Russia backing the Syrian regime.
Date created : 2016-08-10