Ukraine's dual attacks on Russian refineries and Black Sea ports are disrupting domestic fuel supplies and preventing Moscow from redirecting crude into exports. Tanker shipping data show Russian seaborne crude exports averaged 3.46 mln barrels per day in the four weeks to Aug. 23. Exports had earlier risen after Ukrainian strikes curtailed domestic refining, leaving more crude available for export, but that increase is now fading as drone attacks on tankers have cut Black Sea loadings.