Oil futures were up strongly Monday, with Brent crude on track for its first finish above $80 a barrel since August, as investors assess the potential hit to supply from a further tightening of sanctions on Russia’s oil sector.

Oil prices climbed about 2% to a four-month high on Monday on expectations that wider U.S. sanctions on Russian oil would force buyers in India and China to seek other suppliers.

Goldman Sachs is warning of potential upside risks to oil prices following U.S. sanctions on Russia's energy sector, with Brent crude already approaching $80 per barrel and the possibility of hitting $90 under certain scenarios.