An India-bound tanker filled with Russian crude reversed course and is now idling in the Baltic Sea, a sign of potential disruption in oil trade between the two countries after the US tightened sanctions on Moscow, a Bloomberg report said on Wednesday.

The Furia was moving westward in a strait between Denmark and Germany when it turned around on Tuesday and sailed for a short distance before slowing down drastically, ship-tracking data showed. The Aframax is carrying a cargo sold by Rosneft PJSC, according to Kpler.

The vessel’s U-turn in the Fehmarn Belt occurred a week after the US slapped sanctions on state-owned Rosneft and fellow Russian oil giant Lukoil PJSC. Transactions involving the two companies must be wound down by November 21, the Treasury Department had said.

The blacklisting of Russia’s largest producers threatens to cut off a relatively cheap source of crude for Indian refiners. Senior executives at Indian processors have told Bloomberg that flows of Russian oil are expected to plunge as a result.