London - Number-one ocean carrier Maersk has suspended all crew changes aboard its container ships through April 14, the company said in a letter to crew Tuesday. Chile, Argentina, Ecuador, El Salvador, Guatemala, Malaysia, Canada, Denmark and the 27 nations of the European Union have temporarily closed their external borders to most foreign nationals, and the list is growing rapidly: "With the continued spread of the COVID-19 pandemic and the extraordinarily fast-paced closing of borders and cancellations of airline services, today (17 March 2020) we have decided to suspend all crew changes for Maersk operated container vessels effective immediately and for four weeks until 14th April 2020. The decision is based on the need to keep our crew safe while maintaining operations as normal as possible," Maersk said in a statement. "Given the current situation we can better protect our seafarers by suspending the exchange of crew, as this lessens the number of social interactions they need to have. Secondly, the rapid changes to global travel poses a risk of stranding seafarers in transit, in locations from where they are unable to leave or get sufficient assistance." Maersk is not the only firm affected by new international travel restrictions. On Tuesday, leading dry bulk shipping association INTERCARGO called upon port states to continue to permit crew changes as an exception to the rising number of national travel bans. "During this very difficult pandemic, our association wishes to remind societies and nations that without merchant ships and seafarers, cargoes cannot be transported between continents," INTERCARGO said in a statement. "[We wish] to highlight the logistical challenges with the repatriation of seafarers who have completed their sea service and seek their relief and re-joining their families. Though their colleague seafarers are standing by on shore in their home country, the relief process is stalled as many port states have imposed local regulations, travel and quarantine restrictions due to COVID-19, despite the IMO circulars to be mindful of free access to seafarers." Dry bulk ships are the backbone of world trade for non-petroleum commodities, carrying cereals, grains, forest products, mineral ores, coal, fertilizers and breakbulk cargoes like steel and industrial machinery. Without regular crew changes, INTERCARGO noted, seafarers' health and wellbeing will be negatively impacted, with potential repercussions for the safe operation of economically-critical merchant ships. "INTERCARGO urges IMO Member States and all Port States to adopt a pragmatic approach in assisting shipowners and seafarers to overcome these challenges by removing undue hinderance for seafarers to leave or join a ship in their ports," the association said. "Seafarers need our support and compassion with measured, rather than overzealous, restrictions in relation to COVID-19. Without efficient crew changes, the supply chain would break down leading to basic product shortages and greater hardships for people around the world... Banning crew changes in ports brings high risks to crews, ships, ports and society."