Russian gas transiting via Ukraine to Europe dropped by a third Thursday after Kyiv suspended supplies through a key route, Russian energy giant Gazprom said. 

Ukraine's pipeline operator GTSOU said that it was halting gas transport at the Sokhranivka transit point from Wednesday as Russian occupying forces now in control were interfering with operations.

The move comes as Russia's military campaign in pro-Western Ukraine enters its third month. 

Gazprom told the Interfax news agency that supplies transiting Ukraine on Thursday were at 50.6 million cubic metres in total, compared to 72 million cubic metres the day before.

Ukraine's GTSOU on its website provided slightly different figures, saying 53 million cubic metres would transit on Thursday compared to 73 million cubic metres the day before.

Ukraine is a major supply route for Russian gas to Europe and the two sides have kept flows going even after the Kremlin sent troops into Ukraine on February 24.

Germany said Wednesday that it saw a 25 percent drop in supplies of Russian gas flowing through Ukraine.

The drop in Russian natural gas deliveries via Ukraine has fuelled fears that already high gas prices in Europe will climb even further with the fall in supplies.