CHISINAU, Dec 4 (Reuters) - Moldova won't pay a 50% advance to Russia's Gazprom by Dec. 20 for its December gas supplies, Moldova's Deputy Prime Minister Andrei Spinu said on Sunday.

"Moldova has not paid Gazprom's advance for December, and until December 20 will pay only for the gas used in November," Spinu wrote on the Telegram messaging app.

Although it has strong historical and linguistic ties to neighbouring European Union member Romania, Moldova relies on Gazprom for gas imports.

Gazprom has said previously it could shut off gas to Moldova completely unless all contractual obligations are met, having already slashed supplies by around 40% in November.

Spinu said that Moldova, a former Soviet republic, would not pay for Gazprom gas pumped to the breakaway Moldovan region of Transdniestria, which borders Ukraine and is run by pro-Russian separatists.

"The obligation to pay for 5.7 million cubic meters of gas remains with Transdniestria," he said. (Reporting by Alexander Tanas, writing by Max Hunder Editing by Gareth Jones, Kirsten Donovan)