UNITED NATIONS, Dec 20 — Russia, backed by China, on Friday cast its 14th Security Council veto since the start of the Syrian conflict in 2011 to block cross-border aid deliveries from Turkey and Iraq to millions of Syrian civilians.

The resolution drafted by Belgium, Kuwait and Germany would have allowed cross-border humanitarian deliveries for a further 12 months from two points in Turkey and one in Iraq. But Russia, an ally of the Syrian government, wanted to approve only two Turkish crossings for six months and had proposed its own draft text.

The remaining 13 members of the Security Council voted in favor of the resolution. A resolution needs at least nine votes in favor and no vetoes by Russia, China, the United States, Britain or France to pass.

The American ambassador, Kelly Craft, told the council after Russia and China’s vetoes that she was in a state of shock as the consequences “will be disastrous.” She described Russia and China’s opposition as “reckless, irresponsible and cruel.”