India, June 1 -- The reaction from the Kremlin came quickly. By Monday morning, Dmitry Peskov was at the podium calling it piracy.

France and its allies had spent Sunday boarding the Tagor, a sanctioned oil tanker that had departed from the Russian Arctic port of Murmansk and was sailing roughly 400 nautical miles off the tip of Brittany in the Atlantic Ocean. By the time Peskov spoke, the vessel was being escorted to anchorage for inspection - the fourth time since September that French naval forces had stopped a ship they believe belongs to Russia's shadow fleet, the sprawling network of aging tankers and shell companies Moscow has assembled to keep its oil moving despite Western sanctions.

"We consider such actions illegal, they bor...