Austria announced Thursday a 15% decrease in deliveries of Russian gas.
It is yet to be established if the reason for the decline was technical, such as a damaged compressor station, or political.
At the same time, sources of Austrian energy group OMV said it had been informed by Russian partners about a supply reduction.
Slovakia also complained of a 10% decrease in supplies of natural gas from Russia.
On Wednesday, Poland and Germany reported substantial declines.
Russian gas giant Gazprom has rejected accusations of diminishing gas supplies.
Austria will not be affected by the move as its gas storage facilities are 100% full and gas consumption is low due to the temperatures, according to Austrian daily Die Presse.
According to estimates, the country can rely on its gas reserves for at least three months.