Ali Kushayb, a former head of the feared Janjaweed militia, took part in an attack with government forces in central Darfur in April, Bensouda told the 15 - nation Security Council.
Kushayb, President Omar al - Bashir and two other top Sudanese officials are wanted by the ICC for crimes against humanity and war crimes in the 10 - year - old conflict, which the UN says has left more than 300,000 dead.
Witnesses reportedly saw Kushayb taking part in an attack with the Sudanese Central Reserve Forces and other government - linked militia on the town of Abu Jeradil in April, Bensouda said.
More than 100 civilians were killed and more than 30,000 civilians fled into neighboring Chad as the attackers " shot indiscriminately, burned homes and shops, stole livestock and looted goods, " Bensouda said.
The prosecutor said some observers had suggested that the government had staged the attack to " appease " members of two tribes who were in the Janjaweed and other militias and help them get land from rival groups in the town.
Kushayb led the Janjaweed when it staged mass attacks on local tribes who staged an uprising against the Khartoum government at the peak of the conflict.
Bensouda also noted " with concern " allegations that other war crimes suspects, Ahmad Harun and Abdel Raheem Hussein, had been involved in new crimes elsewhere in Sudan.
She complained at the lack of Security Council action over President Bashir ' s travels to countries that are ICC members and had failed to arrested the Sudanese leader.
" It is a matter of great concern that this council has failed to act " on any formal complaint made by the ICC, she said.
Bensouda said she was presenting her latest report on Darfur to the council " with a deep sense of frustration, even despair. "
" Regrettably, each briefing has been followed by inaction and paralysis within the council while the plight of victims of crimes committed in Darfur has gone from bad to worse, " she said.
Bensouda has already said this year that her office is considering new charges over Darfur, which was referred to the ICC by the Security Council in 2005. The UN says that more than 300,000 people have been displaced by a surge in the conflict this year.