(Reuters) – Russian gaz flows via Ukraine to Europe fell 25% on Wednesday, after Kyiv stopped using a major transit route. It blamed interference from occupying Russian troops. This is the first disruption of exports via Ukraine since the conflict started.

Even after Moscow’s “special military operations”, Ukraine has been a main transit route for Russian gaz to Europe. The rest of the Russian gas flowing to Europe is handled by about 8% at the transit point.

Gazprom, which is controlled by the Kremlin, has a monopoly over Russian gas exports via pipeline. However, volumes were still seen at 72,000,000 cubic meters (mcm), on Wednesday. This was down from 95.8 Mcm Tuesday.

GTSOU operates Ukraine’s natural gas system and announced on Tuesday that it would stop gas flowing through Sokhranivka transit points. This point was said to have delivered nearly a third the fuel it claims it has received from Russia.

The company declared “force majeure” as it would redirect deliveries to Europe via the Sudzha entry point. This is the largest of Ukraine’s crossing points.

Through Ukraine’s Luhansk, the gas pipeline runs via Sokhranivka. A portion of this region has been controlled by pro-Russian separatists. Sudzha is further to the north-west.

Gazprom claimed Tuesday that all volumes could not be transferred to Sudzha, according to GTSOU.

On Wednesday, Gazprom provided data that suggested Sudzha was used. GTSOU data indicated that gas transit volumes declined following the denial of Russian gas nominations via Sokhranivka’s entry point on May 11.

According to data provided by TSO Eustream in Slovakia, daily nominations fell for Russian gas delivery from Ukraine via Slovakia on Wednesday. The data indicated that nominations through the Velke Kapusany borderpoint were approximately 717,923 megawatthours (MWh), compared to 883,844MWh on Tuesday.