Several European companies have stopped ships carrying Russian oil in violation of European sanctions.
New sanctions adopted last month allow EU countries to sell oil - a major source of income for Russia - or other cargo seized from the ships.
Putin has called the measures “piracy.”
"We will be forced to respond in kind," Putin said aboard a cruiser off Sakhalin Island, where the Russian navy was conducting military exercises.
Moscow will act “wherever we ourselves deem it necessary and appropriate - anywhere,” he added.
Swedish court documents seen by AFP earlier in August showed that Stockholm will hand over a seized Russian ship to Kyiv, suspected of transporting grain from occupied Ukraine.
