The UN Security Council on Wednesday condemned the July 8 attack and suggested it could be considered a war crime.
The council's non-binding statement "condemns in the strongest possible terms" the "unacceptable act of extreme violence".
The council statement came as fears of retaliation rose two days after the chief prosecutor of The Hague-based International Criminal Court (ICC) sought an arrest warrant against Omar al-Bashir, Sudan's president.
Luis Moreno-Ocampo, the ICC prosecutor, accused al-Bashir on Monday of masterminding a genocidal campaign against three ethnic groups in Darfur.
Moreno-Ocampo requested his arrest warrant on charges of genocide, crimes against humanity and war crimes.
If granted, the warrant would be the first ever issued by The Hague-based court against a sitting head of state.
A high-level governmental committee, set up by al-Bashir to focus on the arrest request and its likely fallout, met on Wednesday.
Imad Ahmed, a government press office spokesman, said the committee "discussed what happened at the International Criminal Court and its effect on peace agreements".
The Darfur conflict broke out in 2003 when ethnic minority fighters took up arms against the Arab-dominated regime in Khartoum and state-backed groups.
The UN says 300,000 people have died and more than 2.2 million displaced in the conflict.
Khartoum puts the number dead at 10,000.