Bloody clashes in North Darfur have killed more than 100 people, UN High Commissioner for Refugees Filippo Grandi said in a tweet on his official account.
"There are shocking reports of horrific sexual violence against women and girls," he added.
"This will worsen unless the parties to the conflict agree to end a fight that is destroying Sudan."
Justice & Equality Movement official Sudan Hassan Ibrahim Fadl said Wednesday that armed militias killed West Darfur Governor Khamis Abakr.
Since April 15, the regular army headed by Abdel Fattah al-Burhan and the paramilitary Rapid Support Forces commanded by his former deputy Mohamed Hamdan Daglo have been locked in urban combat that has left whole neighbourhoods of the capital Khartoum unrecognizable, AFP reported.
The fighting quickly spread to the provinces, particularly the western region of Darfur, and has killed at least 1,800 people, according to the Armed Conflict Location and Event Data Project's (ACLED) latest figures from last month.
