U.S. says Cuba is prohibited from taking Russian oil as two tankers head to island

KEY POINTS

The U.S. Treasury Department has made clear that Cuba is not allowed to take delivery of Russian crude.

The warning comes at a time when two tankers carrying Russian oil and gas are thought to be on their way to Havana.

The fuel-starved Caribbean island is facing its biggest test since the collapse of the Soviet Union under a U.S. oil blockade.