Ukraine's state energy firm Naftogaz said Wednesday that Russia's OAO Gazprom has cut off all gas supplies to Europe through Ukraine.
The gas shipment cutoff began at 7:44 a.m. (5:44 GMT), according to reports.
About 80 percent of all of Russia's gas supplies to Europe go through Ukraine.
The move will stop all deliveries to Austria, the Czech Republic and Slovakia, according to Bloomberg.
Ukraine admitted to using some of the gas supplies to power its pumping system, according to the Associated Press.
Gazprom had previously said it would cut off supplies if Ukraine delayed transport of fuel for European customers.