The cost of sending some aid to Sudan — the world’s largest displacement crisis — has more than doubled due to the Iran war, the UN refugee agency says, Reuters reports.

Heightened insecurity around key Gulf shipping routes, including the Strait of Hormuz, as well as congestion at ports, rising fuel prices and higher insurance premiums have all hampered the delivery of aid, particularly in Africa, the agency said.

Ships with aid that previously passed from Dubai through the Strait of Hormuz are being replaced by ships coming from Europe around the Cape of Good Hope, adding up to 25 days to delivery times, UNHCR spokesperson Carlotta Wolf told reporters in Geneva.

“People in dire need are receiving things that are ready later than what’s needed,” she said.