Cubans wait hours for buses to arrive. In Havana, drivers wait in long lines at gasoline stations.  Both are signs of the effect of the United States’ sanctions on Cuba and its main ally, oil producer Venezuela.  Cuban President Miguel Diaz-Canel recently warned the country’s citizens of difficult times because of limited fuel imports. He urged Cubans to show unity and do their best to increase energy efficiency.

The U.S. government announced sanctions on Cuba’s state-operated company Cubametales in July. It also took action against a group of shipping companies and their ships.  This week, the U.S. Treasury Department targeted four other companies and ships they own or operate that bring Venezuelan oil to the island.

For many years, Cuba has purchased crude oil from its allies. It also imports fuel to help satisfy the nation’s demand for oil, about 145,000 barrels a day. It is used to power Cuban factories, industrial centers, gas stations, airports and homes. Fuel shortages have slowly grown worse since Cuba’s main ally, Venezuela, started reducing oil shipments as far back as 2016 after its own production decreased. Venezuela’s economy has since entered a deep recession. The two countries signed an agreement in 2000. Under the deal, Cuba is able to pay for Venezuelan oil by offering medical help and other services to the South American country.