Russian Energy Minister Alexander Novak said on Tuesday that the Iran-related sanctions, imposed by the United States against a ministry unit, were "baseless".
Last month the United States has moved to disrupt an Iranian-Russian network that it said had sent millions of barrels of oil to Syria and hundreds of millions of dollars to indirectly fund militant groups Hamas and Hezbollah.
Among various individuals and companies, it put under sanctions state-owned Russian company Promsyrioimport, a subsidiary of the Energy Ministry, which the U.S. Treasury alleges had facilitated shipments of Iranian oil to Syria.