Hungary on Monday noted a 25-percent drop in gas pressure at its border with Ukraine, as Russia had cut off gas supplies to Ukraine over a price dispute.

"Twenty-five percent less natural gas is coming in," said Szabolcs Ferenc, spokesman for the leading Hungarian energy group Mol.

"It is impossible to tell whether this drop is caused by the Ukrainians or the Russians but this is a question concerning not just Hungary, but also Austria, Italy, the Czech Republic," Ferenc told the commercial radio station Klubradio.

According to the spokesman, major consumers of natural gas in Hungary might have to switch to oil, while common users won't feel much pinch from the reduced supply.

Meanwhile, countries like Poland, Austria and Slovakia also noted drops in Russian gas deliveries.

Russian gas giant Gazprom cut off natural gas supply to Ukraine on Sunday after Kiev rejected Russia's demand to more than quadruple the price from the 50 U.S. dollars per 1,000 cubic meters over the past year.

The move also poses potential threats to its European consumers, as most of the gas they buy from Russia transited from Ukraine.