Cuba's power grid has failed for the second time in less than a week, due to a US-imposed oil blockade. The Cuban Electric Union, which reports to the Ministry of Energy and Mines, announced a total blackout across the island without giving a cause. The union later clarified that the outage was caused by an unexpected failure of a generating unit at the Nuevitas thermoelectric plant in Camaguey province. This comes as an international aid convoy arrives in Havana to bring desperately needed medical supplies, food, water and solar panels to the island. No oil has been imported to Cuba since January 9, impacting the power sector and causing airlines to suspend flights. The situation has worsened since Venezuela's socialist leader, Nicolas Maduro, was captured in a US military operation.