UNITED NATIONS (Reuters) - The head of the United Nations will name former German president Horst Koehler as his new envoy for Western Sahara, in charge of restarting talks between Morocco and the Polisario independence movement over the disputed territory.

FILE PHOTO: Former German President Horst Koehler arrives for the state funeral of late German President Roman Herzog in Berlin, Germany, January 24, 2017. REUTERS/Steffie Loos/POOL/File Photo

The United Nations Security Council in April backed attempts to re-enter negotiations over Western Sahara, which has been contested since 1975 and where Morocco and Polisario fought a war until a 1991 ceasefire.

“Following the usual consultations, I intend to appoint Horst Koehler of Germany as my personal envoy for Western Sahara,” U.N. Secretary General Antonio Guterres said in a letter to the Security Council released by the U.N. on Friday.

Tensions increased in Western Sahara last year when Moroccan forces faced off with a brigade of Polisario forces in the remote Guerguerat area near the Mauritania border. Both sides withdrew their forces this year.

Before serving as Germany’s president from 2004 to 2010, Koehler was managing director of the International Monetary Fund. He also has worked for the U.N. in development programs and on a panel for the African Development Bank.

Morocco claimed Western Sahara after former colonial power Spain left, but Polisario fought a guerrilla war for independence for the Sahrawi people there until the U.N.-backed ceasefire.

U.N. talks have failed to broker an agreement on how to decide on self-determination. Morocco wants an autonomy plan under Moroccan sovereignty. But the Polisario wants a U.N.-backed referendum that would include the question of independence.

Relations between Morocco and the U.N. hit a low last year after then-U.N. Secretary-General Ban Ki-moon used the word “occupation” to describe Morocco’s annexation of Western Sahara. Morocco expelled dozens of U.N. staff working for the mission there known as MINURSO.

Guterres on Friday expressed concern over the plight of tens of thousands of Sahrawi refugees in Algeria who will see their food rations cut due to lack of funding, his spokesman, Farhan Haq, told reporters.

“Humanitarian aid, including food aid, is a lifeline for these refugees from Western Sahara,” Haq said. “The secretary-general calls on donors to urgently increase their assistance to this often overlooked and vulnerable population.”

Haq said the World Food Programme needs $7.9 million to continue providing food assistance over the next six months.