Russia’s state-owned natural gas company Gazprom warned that this winter, European gas prices might rise by 60% to more than $4,000 per 1,000 cubic meters as the company’s own export and production continue to decline as a result of Western sanctions, Reuters reported.

Since one route was blocked when Moscow pushed soldiers into Ukraine in February and after sanctions sparked a disagreement over the Nord Stream 1 pipeline’s technology, gas flows from Russia, Europe’s largest supply, have decreased this year. As a result, gas costs have increased significantly.