DAKAR (Reuters) - Operational costs of the United Nation's World Food Programme (WFP) will increase by $136 million in West Africa this year because of the global rise in food and fuel prices driven by the war in Ukraine, the agency said on Thursday.

       The additional costs will hamper attempts to relieve a spiralling food crisis in the region fuelled by conflict, drought, pandemic-linked border closures and the impact of Ukraine's crisis on food prices and availability.

       The WFP was already struggling to expand its response to an "unprecedented food and nutrition crisis" in West Africa, and was forced to cut rations in seven countries because of lack of funding even before Russia's Feb. 24 invasion of Ukraine.

       "With the unfolding conflict in Ukraine, ports and suppliers are no longer accessible with shipments from the wider Black Sea delayed or simply cancelled," WFP Regional Director Chris Nikoi said in a statement.

       Six West African countries import 30-50% of their wheat from Russia and Ukraine, according to the United Nations Food and Agriculture Organization.

       Several aid agencies have raised concern about the Ukraine war diverting funds from other crises.

       Acute hunger has quadrupled in West Africa over the past three years, with 43 million people expected to face acute food insecurity by June 2022, according to the WFP.

       (Reporting by Sofia Christensen; Editing by James Macharia Chege and Grant McCool)