Russia vetoed a Western-backed resolution condemning the Crimea referendum at a U.N. Security Council emergency vote Saturday but China abstained, isolating Moscow further on the Ukraine crisis, Agence France-Presse reported.

The draft resolution, which says Sunday’s referendum would have no validity, got 13 votes in the 15-member Council. But it was rejected when permanent member Russia exercised its veto.

An AFP team estimated that around 50,000 people rallied Saturday in central Moscow in protest at Russia’s intervention in Ukraine, a day before the Crimean peninsula is expected to vote on switching to Kremlin rule.

Many of the protesters adopted the chants and slogans of Ukraine’s popular uprising that ousted pro-Moscow president Viktor Yanukovych last month.

Holding Ukrainian and Russian flags, they also shouted: “The occupation of Crimea is Russia’s disgrace” and “Hands off Ukraine.”

On Saturday, Ukraine’s military scrambled aircraft and paratroops to repel an attempt by Russian forces to enter a long spit of land belonging to a region adjacent to Crimea, Reuters reported Ukraine’s defense ministry as saying.

“Units of Ukraine’s armed forces today…repelled an attempt by servicemen of the armed forces of the Russian Federation to enter the territory of Kherson region on Arbatskaya Strelka,” Reuters quoted a ministry statement as saying.

“This was repelled immediately.”

It said the Ukrainian military used aircraft, ground forces and its aeromobile battalion in the operation.

The territory in question is a long spit of land running parallel to the east of Ukraine’s Crimea peninsula, now controlled by Russian forces.