Two boats filled with humanitarian supplies travelling from Mexico to Cuba have been located days after contact with them was lost in the Caribbean, organizers say. The boats were located by the Mexican Navy and the crews are safe, a spokesman for the Nuestra America Convoy said. He did not explain why the two boats - the Friendship and Tigger Moth - had disappeared. They are among several vessels that have sought to carry supplies to the island nation since the US imposed an oil blockade in January, prompting a chronic fuel shortage. The Mexican Navy has not commented on how it located the boats, which departed Isla Mujeres on March 20, and had been due to arrive at their destination on Monday or Tuesday. There are nine crew members - from Poland, France, Cuba, and the US - on board. The vessels are continuing their journey to Havana, the Nuestra America Convoy spokesman said, adding that the convoy remains on track to complete its mission - delivering urgently needed humanitarian aid to the Cuban people. Volunteers and non-governmental organizations have largely spearheaded efforts to deliver humanitarian aid to Cuba since the US embargo on the communist-run country began. The UN has warned that Cuba faces dire supply shortages, with more than 50,000 surgeries cancelled due to fuel constraints and aging infrastructure causing multiple nationwide blackouts. Coupled with shortages of food and medicine, the situation has triggered rare public dissent in the form of street protests. Earlier in the week, the Cuban government celebrated and warmly received another boat that had carried 14 tonnes of humanitarian aid to the island. The vessel, dubbed Granma 2.0 after the boat with which Fidel Castro returned to Cuba to launch its 1950s revolution, delivered solar panels, medicines, baby formula, bicycles, and food. Since the US seized former Venezuelan President Nicolás Maduro in January and cut off the supply of oil from Venezuela, Trump has turned his attention to the Caribbean island and threatened tariffs on any country supplying oil to Cuba. The Cuban government has confirmed it is in talks with the US to resolve their differences but insists that the political system of Cuba is not up for negotiation.\