Russia skipped U.N. Security Council negotiations on Tuesday on whether to extend approval for cross-border aid access into Syria, diplomats said, as China pushed for “solutions” to its concerns about unilateral sanctions and aid transparency.

       The council mandate for the long-running U.N. operation delivering aid into northern Syria from Turkey is due to expire on Saturday. Veto-powers Russia and China are wary of renewing it, while Western members want to re-authorize and expand it.

       U.N. officials say there can be no substitute for the cross-border aid operation, which was first approved in 2014.

       “The cross border aid operation has been the safest and most reliable way of getting aid to people,” Mark Cutts, U.N. deputy regional humanitarian coordinator for the Syria crisis, told an event at the United Nations in New York, organized by Canada, Dominican Republic, the Netherlands, Qatar and Turkey.

       “In the last year we’ve been delivering an average of just over 1,000 trucks a month of aid into northwest Syria. It’s absolutely vital now that we keep this aid operation going,” Cutts said.

       The Security Council is negotiating a resolution, drafted by Ireland and Norway, to authorize aid deliveries through two crossings: one from Turkey and one from Iraq. But Russian U.N. Ambassador Vassily Nebenzia said last week he is only discussing a possible extension of U.N. approval for the Turkish crossing.

       While Russia – an ally of Syrian President Bashar al-Assad -did not show up to negotiations on Tuesday, diplomats said they were still separately engaging with key members. Russia’s U.N. mission did not immediately respond to a request for comment.

       The council first authorized a cross-border aid operation into Syria in 2014 at four points. Last year, it reduced that to one point from Turkey into a rebel-held area in Syria due to Russian and Chinese opposition over renewing all four.

       Russia has said the aid operation is outdated and violates Syria’s sovereignty and territorial integrity. In a swipe at the United States and others, Russia and China have also blamed unilateral sanctions for some of Syria’s plight.

       China’s U.N. Ambassador Zhang Jun said on Tuesday that Beijing wanted to see “solutions” to address concerns about unilateral sanctions on Syria, to increase aid deliveries across front lines within the country, and to boost the transparency of the cross-border aid operation.

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       U.S. Ambassador to the United Nations, Linda Thomas-Greenfield, said the discussion was not about sanctions.

       “It’s a question of the humanitarian needs,” she told reporters, warning that if the one remaining border crossing was closed to aid deliveries: “The repercussions are obvious – people will starve to death.”

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