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 Tiger 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, in Mexico's easternmost state of Quintana Roo, on 20 March, 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 [the Cuban capital] Havana,' the Nuestra America Convoy spokesman said. 'The convoy remains on track to complete its mission - delivering urgently needed humanitarian aid to the Cuban people,' he added. Volunteers and non-governmental organisations have largely spearheaded efforts to deliver humanitarian aid to Cuba since US President Donald Trump's oil embargo on the communist-run country began. The UN has warned Cuba faces 'dire' supply shortages, with more than 50,000 surgeries canceled in Cuba as fuel supply constraints and ageing infrastructure have caused 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 in which [late Communist leader] Fidel Castro returned to Cuba to launch its 1950s revolution, delivered solar panels, medicines, baby formula, bicycles, and food.