Oil flows through the Caspian Pipeline Consortium (CPC), a major export route for Kazakhstan and a significant contributor to global supply, was reduced by 30-40% on Tuesday following a Ukrainian drone attack on a pumping station in southern Russia, Russian officials said.

The attack, which caused no casualties, occurred on the eve of talks between U.S. and Russian officials on ending the war in Ukraine. Kyiv was excluded from the meeting, after which the Trump administration said further talks had been agreed upon.

Russian Deputy Prime Minister Alexander Novak said on Russian television that volumes had dropped by approximately 30-40% compared with pre-attack levels. 

“As a result of the attack, energy equipment, a gas turbine unit, and a substation were damaged,” he said. The CPC pipeline carries crude from companies including Chevron and Exxon Mobil. Novak indicated repairs could take several months.

The pipeline, which ships more than 1% of the daily global oil supply, stretches over 1,500 kilometers (939 miles) and carries crude from Kazakhstan's vast Tengiz oilfield and Russian producers. 

According to Reuters calculations, a 30% cut in CPC shipments could amount to as much as 380,000 barrels per day.

Kazakhstan relies on the CPC pipeline for most of its crude supplies and is the main route for its oil exports. Russia’s state pipeline operator, Transneft, said Kazakhstan would have to reduce exports by 30% to meet its own domestic needs.

The CPC said in a statement that the pipeline “continues to operate” and was pumping oil to tankers on the Black Sea, albeit at reduced levels, while bypassing the damaged station.

Chevron-led Tengizchevroil (TCO), operator of the Tengiz oilfield, said it was monitoring the situation, adding that “production and export of crude oil via the CPC pipeline remain uninterrupted.”

Kazakhstan’s energy ministry also said the country was supplying oil without restrictions, stating that the pipeline from Tengiz to the Black Sea port of Novorossiysk was operating “without the participation” of the Kropotkinskaya pumping station. However, the ministry did not mention the drone attack.

Transneft said at least seven drones packed with explosives and shrapnel attacked the Kropotkinskaya station in Russia’s Krasnodar region, causing “serious damage.”

The General Staff of the Ukrainian armed forces claimed responsibility for the attack, saying it had targeted Russian energy infrastructure, including the CPC pumping station and the nearby Ilsky oil refinery. 

Shareholders in the CPC include U.S. majors Chevron and Exxon Mobil, as well as the Russian state, Russian firm Lukoil, and Kazakh state company KazMunayGas.