PARIS, Nov 21 (Reuters) - Moldova warned its people on Monday to brace for a harsh winter as it was facing an "acute" energy crisis that risked stoking popular discontent with Russia's war in Ukraine threatening energy supplies and pushing up prices.

About 50 countries and institutions met in Paris on Monday to pledge aid for Moldova, which is wedged between Ukraine and Romania, as fears mount that it could be further destabilised by the conflict.

"This war is endangering the supply of electricity and gas. We are not certain we can find enough ... to heat and light our homes, and even if we do, the prices are unaffordable for our people and economy. This could jeopardise our social peace and security," President Maia Sandu told delegates in a speech.

"I know everyone in Europe pays a very high price for energy but these same prices have a much more ruinous impact on our country and people."

In remarks reported on Sandu's website in Chisinau, the president also warned participants that Moldova's democracy was under attack by what she described as Russian-backed criminal groups organising weekly protests demanding her resignation.

"Anti-government protests in Chisinau - this is part of a hybrid war against Moldova directly financed by Russia, which every week pays participants to take part," the website quoted her as saying. "We must work together to stop these groups."

Sandu was referring to the party of exiled businessman Ilan Shor, which has organised the protests against high prices.

Shor was convicted of fraud in connection with a $1 billion bank scandal. The chief suspect in that fraud, magnate Vlad Plahotniuc, is also outside Moldova, his whereabouts unknown.

Sandu said Moldova expected an 8 percent drop in gross domestic product in 2022 against previous zero growth forecasts.

Moldova has felt the effects of rising food and energy prices and refugees arriving in the country of 2.5 million people, which has taken more Ukrainian refugees per head than any other country.

Although it has strong historical and linguistic ties to neighbouring European Union member Romania, Moldova relies exclusively on Russia's Gazprom for gas imports and is largely dependent on Russian energy.

CUTS IN RUSSIAN GAS SUPPLIES

With winter arriving and Moscow slashing natural gas supplies by about 40%, its ability to supply enough electricity to its population is in doubt.

Donor conferences in Berlin and Bucharest earlier this year brought pledges of 659 million euros ($674.68 million) and 615 million euros, respectively. But officials involved in those conferences said the figures included some repeated pledges, project financing and promises to inject money into the economy rather than direct budgetary support.

One diplomatic source attending the conference said there had not been a great deal of new pledges, but French President Emmanuel Macron told delegates Paris would provide an additional 100 million euros to help Moldova's immediate needs.

"We must not yield to (war) fatigue or the idea this will end quickly," Macron said.

Germany had pledged about 32.5 million euros for renewable energy, infrastructure and refugee aid, diplomatic sources said.

"We will not leave Moldova alone in cold or darkness, nor in a looming recession," German Foreign Minister Annalena Baerbock told reporters. ($1 = 0.9768 euros) (Reporting by John Irish and Luiza Ilie; Additional reporting by Alexander Ratz and Alexander Tanas in Chisinau; Editing by Tomasz Janowski, Ron Popeski and Grant McCool)