A fire broke out at the Ñico López Refinery in Havana, Cuba, on Friday. Black smoke was seen rising from the site near where two oil tankers were moored in Havana Bay. Cuba's energy ministry said the fire was quickly brought under control. No injuries were reported. An investigation into the blaze has been launched. The incident comes as Cuba faces a deepening fuel crisis. The crisis worsened after the United States blocked oil shipments from Venezuela, a close ally of Cuba. Before the US restrictions, Venezuela sent about 35,000 barrels of oil daily to Cuba. The situation intensified after the US military seized Venezuela's former president Nicolás Maduro in a January raid in Caracas and confiscated Venezuelan oil tankers. US President Donald Trump urged Cuban leaders to "make a deal" or face consequences, following the cut in oil and money flows from Venezuela. The US also announced new tariffs on countries that sell oil to Cuba. Due to fuel shortages, Cuba has introduced rationing and cut back public services. Electricity outages have affected hospital emergency wards, dialysis patients, and water pumping stations. Aviation fuel shortages caused airlines to suspend flights to Cuba. Some countries, including the UK, warn citizens to avoid non-essential travel to the island. The UK's Foreign, Commonwealth and Development Office stated, "Authorities have introduced fuel rationing, scaled back public services, and made temporary changes to healthcare, education, transport and tourism operations to conserve severely limited energy supplies." To assist, two Mexican ships carrying 800 tonnes of humanitarian aid arrived at Havana Bay on Thursday. United Nations human rights experts called the US restrictions an "extreme form of unilateral economic coercion." UN human rights chief Volker Türk expressed he was "extremely concerned" about Cuba's worsening crisis. US economic and trade embargoes against Cuba have been in place since 1960, greatly impacting the island's access to vital fuel supplies.