Ukraine said it had struck 11 Russian vessels on the Sea of Azov, choking off a waterway that has become vital for Moscow.
Russia ships vast amounts of oil, steel, and grain through the Kerch Strait to the Black Sea, but traffic has slowed to a trickle in recent days after Ukraine claimed to have hit more than 100 vessels.
The attacks have heaped pressure on Russia’s economy, which is already grappling with the worst fuel shortages since the fall of the Soviet Union. Some fear that, as Russia’s battlefield progress in Ukraine stalls and domestic pressure rises, President Vladimir Putin may try to escalate his war as he looks for a breakthrough to sell as a victory.