Russia stopped oil shipments to Poland after pipeline operator Transneft didn’t receive documents necessary for the crude to be allowed to leave the country.

The producer of the oil that was due to be delivered to Poland in the final days of February didn’t send shipment orders or the transit payment, Transneft spokesman Igor Dyomin said on Monday. The pipeline operator’s loading schedule was also changed to exclude flows to Polish refineries, he said. 

In order to deliver crude to foreign markets, Transneft requires an export plan approved by Russia’s Energy Ministry and shipment orders from oil producers. 

The halt came a day after Russia’s invasion of Ukraine reached the one-year mark. Poland has been among the staunchest backers of Kyiv, sending humanitarian aid, weapons and accepting some 1.5 million refugees. It also was the first European country to have its gas deliveries cut off by Russia in 2022, days after the start of the war.

On Saturday, Poland’s largest oil company, PKN Orlen SA said it had unexpectedly stopped receiving oil via the northern leg of the Druzhba pipeline. Flows for this month were planned at about 220,000 tons — roughly 58,000 barrels a day — down by more than half from January shipments. 

PKN Orlen said on Monday that it doesn’t have any direct business or commercial relations with Transneft. It has a supply agreement with Russian oil producer Tatneft PJSC, which uses Transneft’s services to ship crude to foreign buyers. 

Tatneft didn’t respond to a request for comment about the lack of shipment orders to Poland. 

According to Transneft’s original export plan, Russian oil flows to Poland were scheduled for the last 10 days of February, Dyomin said. Russia’s Energy Ministry didn’t respond to a request for a comment about changes in the export plan. 

Separately, Transneft said on Monday that it has started shipping Kazakh oil via Poland through the Druzhba pipeline, for final supply to Germany. 

While pipeline flows are excluded from the EU’s ban on oil imports from Russia, Poland has repeatedly said it plans to stop buying crude from the country entirely. But without formal European sanctions, Warsaw was unable to cancel the only remaining contract with a Russian supplier. 

Russian oil accounts for about 10% of Polish supplies after the country rushed to slash imports following President Vladimir Putin’s invasion of Ukraine. Warsaw-listed Orlen said consumers won’t be affected by the Druzhba halt, for which it said it had prepared. 

The cut-off of February flows came just days before Russia plans to curb its production 500,000 barrels a day in March in retaliation for western energy sanctions. The reduction is equivalent to about 5% of the nation’s output in January. 

The southern leg of Druzhba, which supplies crude to Hungary, Czech Republic and Slovakia was operating normally on Saturday.