A Ukrainian drone strike has hit a pumping station on Kazakhstan’s main oil export pipeline in Russia, its operator said on Monday, reducing flows to the Black Sea port of Novorossiisk.

A drone struck the Kropotkinskaya station in the southern Krasnodar region, where work was halted to investigate the damage, the Caspian Pipeline Consortium (CPC) said in a statement.

A source at Ukraine's SBU security service said that Kyiv had hit the pumping station and the nearby Ilsky oil refinery using drones. The source said both facilities were supporting Russia's military action in Ukraine.

Ukrainian drones have repeatedly targeted Russian energy infrastructure in recent months, including in the southern Krasnodar region.

The CPC pipeline, whose shareholders include U.S. energy majors Chevron and ExxonMobil, handles almost all of Kazakhstan's oil exports, which account for around 1% of global daily supply.

Kazakhstan's energy ministry said oil loadings at the Tengiz oilfield continued as normal. The strike comes a day before the United States and Russia are scheduled to hold talks on ending the war in Ukraine with U.S. Secretary of State Marco Rubio set to meet Russian Foreign Minister Sergei Lavrov in Saudi Arabia.