UNITED NATIONS (Reuters) - Truckloads of medical aid for civilians in Syria’s northeast is stuck in Iraq, the United Nations aid chief said on Wednesday, after Russia and China prevented the U.N. Security Council from renewing authorization for the cross-border deliveries.

Earlier this month, the council allowed a six-year-long cross-border aid operation to continue from two places in Turkey, but dropped crossing points from Iraq and Jordan due to opposition by Russia and China. In December the two countries vetoed a bid to extend approval for both the crossing points in Turkey and Iraq.

“Some 400,000 medical items planned for delivery are stuck on trucks in Iraq and unable to cross,” U.N. aid chief Mark Lowcock told the council on Wednesday.

“The secretary-general (Antonio Guterres) has asked members of this council for their support in getting agreement that these items can be brought in,” he said. “As of today, they remain in Iraq.”

Lowcock said that the World Health Organization had warned that the removal of the Iraq crossing point from the cross-border aid operation would lead to “a reduction in the medical services available and a growing shortfall of medical supplies.”

Russian U.N. Ambassador Vassily Nebenzia has dismissed concerns about closing the Iraq border crossing because he said the situation on the ground had changed and humanitarian aid was being delivered to the northeast from within Syria.

“Instead of whipping up passions here, we would recommend that OCHA (Office for the Coordination of Humanitarian Affairs) as quickly as possible establish effective cooperation with the legitimate authorities in Damascus,” he said on Wednesday.

Deputy U.S. Ambassador Cherith Norman Chalet said the closing of the Iraqi border crossing had cut off 40 percent of U.N. medical equipment and supplies to northeastern Syria.

“Russia has denied principled humanitarian aid for those in need throughout Syria for over eight years. Now, with China blindly following its lead, Russia has escalated its campaign to restrict humanitarian access in Syria through a cynical and politicized effort,” she told the council.

China’s U.N. Ambassador Zhang Jun rejected the U.S. accusation as groundless.

“Every country is entitled to vote its own position,” Zhang said. “Do you think we’re still in a period of colonialism and the whole world has to side with the U.S. and the UK? The time has long gone.”

Lowcock said the United Nations was in talks with all parties, including the Syrian government, “to ensure reliable and adequate supply lines and humanitarian capacity in the northeast” and called for the “crucial” reopening of a key highway.

“No United Nations convoys containing medical supplies have gone from Damascus to the northeast this month. There were three airlifts in December. There have been none so far in January,” Lowcock told the council.