Moscow/Washington, Jan. 7 -- Russia has dispatched a submarine and surface vessels to escort an oil tanker across the North Atlantic as the ship faces the prospect of interception by the US over alleged sanctions violations, sharpening an already volatile confrontation over illicit oil flows.

US officials said the tanker, now sailing between Iceland and the British Isles, is being pursued under Washington's expanded enforcement campaign against sanctioned energy shipments.

The vessel, formerly named Bella 1 and now operating as Marinera, was previously flagged to Guyana and has since been re-registered under the Russian flag. It has a history of transporting Venezuelan crude and is accused by US authorities of breaching sanctions linked t...