UNITED NATIONS (AFP) - The UN Security Council will meet in an emergency session Saturday to vote on a Western-backed resolution denouncing the upcoming referendum in Ukraine's Crimea on switching over to Kremlin rule, diplomats said Friday.

The meeting, which is set to begin at 11:00 am (1500 GMT), was called at Washington's request. Diplomats say they expect Russia to veto the resolution.

The position of veto-wielding China - which often backs Russia at the council, especially on Syria-related votes - is more uncertain this time around, one Western diplomat said.

Beijing has long defended the need to respect territorial integrity and does not back interference in the internal affairs of other countries.

"The only objective of a resolution would be to get the Chinese to abstain and isolate Russia further," another council diplomat said.

The resolution was drafted by the United States in very measured terms so that it could be accepted by Beijing.

It does not target Russia specifically and does not explicitly call for Russian troop reinforcements to be withdrawn from the Crimean peninsula, where Moscow has military bases.

It also does not threaten sanctions.

From a tactical point of view, Western diplomats are hoping the council will back the resolution before the referendum takes place on Sunday in the Black Sea peninsula, which is an autonomous region of Ukraine and has a large ethnic Russian population.