The United Nations human rights chief warned on Monday that widening and intensifying violence in Sudan, as well as the rising use of drones, could lead to more death and displacement.

"The international community is on notice that, unless action is taken without delay, this conflict is on the cusp of entering yet another new, even deadlier phase," the high commissioner for the UN Human Rights Office, Volker Turk, said in a statement.

Turk warned that armed drones have now become the leading cause of civilian deaths. Drone strikes accounted for 80% of all conflict-related civilian deaths, with at least 880 people killed by an unmanned aerial vehicle between January and April this year, according to OHCHR data.

Most were recorded in the Kordofan region. Twenty-six civilians were reportedly killed following drone strikes on Al Quz, in South Kordofan, and near El Obeid, in North Kordofan, on May 8, according to OHCHR.

Kordofan and Darfur, in western Sudan, have ​been focal points of violence, including sexual violence and ethnically charged killings, in the civil war that ​erupted in April 2023 between the Sudanese army and the paramilitary Rapid Support Forces.

The use of drones by the Rapid Support Forces and the Sudanese Armed Forces is also spreading to other regions including Blue Nile, White Nile and Khartoum.

Civilians risk further displacement from a likely intensification of hostilities, particularly in the SAF-controlled cities of El Obeid and Dilling in South Kordofan, Turk said.

Increased violence could hamper delivery of critical aid supplies as parts of the country, including Kordofan, face an increased risk of famine and acute food insecurity, he said. 

"An intensification of hostilities in the coming weeks, as the parties seek to gain or consolidate control of territory amid shifting conflict dynamics, risks hostilities expanding even further to central and eastern states, with lethal consequences for civilians across enormous areas," Turk said.

Drones were enabling fighting to continue during the rainy season, which had previously caused a lull in ground operations, Turk said. He called for robust measures to prevent the transfer of arms, including advanced armed drones, to the warring parties.