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.
This is our hemisphere/continent. We’re as touchy about it as Russia is about Europe and parts of Asia.