Cuba's national electricity grid collapsed on Sunday, plunging the entire country, including Havana, into darkness. The state utility Union Nacional de Energía (UNE) reported a total disconnection of the national system. Residents in affected areas gathered on streets, some setting piles of trash on fire or banging on pots and pans to express frustration. The Ministry of Energy said that protocols to reactivate the grid were underway. The power outage follows a series of nationwide blackouts, including a collapse in western Cuba the day before. The grid failures have disrupted water supplies and halted ceiling fans, making daily life difficult. The United States has authorized the arrival of a Russian tanker carrying 100,000 tons of crude oil in March, but those reserves have been exhausted. In addition to an existing oil blockade, the United States has increased sanctions on Cuban state-owned enterprises, leading some foreign firms to suspend operations. The United States also indicted former president Raul Castro over the downing of two civilian aircraft three decades ago. Negotiations between Havana and Washington have yielded limited results. Havana has implemented free-market reforms intended to stimulate the economy. The blackout highlights persistent energy challenges with no apparent immediate solution.