The United Nations envoy to Sudan, a key mediator in the country’s brutal conflict, is no longer welcome in the country, Sudanese authorities have said.

A terse statement issued by Sudan’s Foreign Ministry comes just weeks after the head of the country’s military, General Abdel Fattah Burhan, demanded in a letter to envoy Volker Perthes that he should be removed from his post.

UN secretary-general Antonio Guterres has been notified that Mr Perthes has been formally declared “persona non grata”, the Foreign Ministry said.

Since April 15, Sudan’s military, headed by Mr Burhan, and the paramilitary Rapid Support Forces (RSF), led by General Mohammed Hamdan Dagalo, have been locked in a violent power struggle that has killed more than 860 civilians, according to the Sudan’s Doctors’ Syndicate which tracks civilian casualties. The actual death tally is likely to be much higher.

Later on Friday, the military and the RSF agreed to a new 24-hour ceasefire to start at 6am local time on Saturday, Saudi Arabia and the US said in a joint statement published by the state-run Saudi Press Agency.

The day-long truce, brokered by Washington and Riyadh, will be the conflict’s eighth ceasefire deal. All past agreements have foundered.

Last week, the two mediating nations suspended formal peace talks that had been taking place in the Saudi coastal city of Jeddah since late May, accusing each other of repeated ceasefire violations. The same day, Washington announced the imposition of sanctions against key defence companies tied to the military and the RSF, along with visa restrictions.

Despite the breakdown, Washington and Riyadh said they have remained in contact with representatives from both forces in the hope of reviving formal peace talks.

Mr Perthes has been a key mediator in Sudan since being appointed as special envoy in 2021, first during the country’s failed attempts to transition to democracy and then as relations between the military and the RSF deteriorated. Fighting exploded in April.

Mr Perthes’ native Germany condemned the announcement.

“The international community, including the German government, continues to stand fully behind Mr Perthes and his efforts,” said Andrea Sasse, spokesperson for the Foreign Ministry, in Berlin.

She said Mr Perthes will continue to do his job from Kenya, from where he is supporting efforts in Jeddah to get the warring parties to the table and secure a ceasefire.

Mr Perthes was in Addis Ababa, Ethiopia’s capital, on Thursday meeting representatives from the African Union and the eight-nation eastern Africa bloc known as IGAD.

In recent months, the German diplomat has received death threats and numerous calls to resign.

In his letter last month, Mr Burhan accused Mr Perthes of “being partisan” and negatively contributing to pre-war talks between the generals and pro-democracy groups in the weeks building up to the conflict.

Responding to these allegations, Mr Volker told The Associated Press that those who threatened him were marginal “extremists” and that there is a wide appreciation of UN efforts in Sudan, which has relocated its headquarters to the coastal city of Port Sudan.

The conflict between the two generals has reduced Khartoum to an urban battlefield, with many districts of the city without running water or electricity.

There have been reports of widespread looting and sexual violence, including the rape of women and girls in Khartoum and the western Darfur region, which have seen some of the worst fighting in the conflict.

Almost all reported cases of sexual attacks were blamed on the RSF.

On Wednesday, 297 children were rescued from an orphanage in Sudan’s capital after being trapped there while fighting raged outside, Unicef said. The evacuation came after 71 children had died from hunger and illness in the facility since mid-April.