In a short resolution, the Council unanimously agreed to extend until December 3, 2023 the UN Integrated Transition Assistance Mission in Sudan (UNITAMS), a limited duration that underscores the African country's delicate situation.
Sudan's army chief Abdel Fattah al-Burhan last week accused Perthes of stoking the brutal conflict the army is fighting against paramilitaries.
In a letter to UN Secretary-General Antonio Guterres, the army chief also asked him to name a replacement for Perthes, saying the envoy had committed "fraud and disinformation" in facilitating a political process which broke down into six weeks of devastating urban warfare.
At the end of a closed Security Council meeting on Wednesday, Guterres repeated his "full confidence" in Perthes. Several other Council members also voiced their support for the UN envoy.
The next six months will provide the Security Council with the necessary time "to assess the impacts of [...] UNITAM's ability to fulfill its vital mandates," deputy British ambassador James Kariuki said.
US Deputy Ambassador Robert Wood voiced "regret that this council was unable to find consensus on an updated mandate." He said he hoped that the Council in coming months would agree on a resolution that "empowers the mission to better support an end to the conflict, protection of human rights (and) unhindered humanitarian assistance."
The resolution adopted Friday calls on the secretary-general to continue to report on the mission every three months. The next report is expected by August 30.
Perthes, who was in New York when Barhan made his accusation, is expected to return "to the region" in the coming days, first stopping in Addis Ababa to meet with African Union officials, a spokesperson for the secretary-general said.
In a separate statement also adopted on Friday, the Security Council reaffirmed its "support" for the mission and called for "continued engagement."
The 15 members also resolved to "condemn the attacks against the civilian population," UN personnel and humanitarian actors, as well as the looting of humanitarian supplies.
UNITAMS, created in June 2020 to support Sudan's democratic transition after the fall of Omar al-Bashir a year earlier, had since been renewed annually for a year.