The same demonstrators took to the streets earlier in the week, before Ban's statement was issued, protesting a decision by the government to halt apparently successful military operations against the rebels north of Goma. Those protests were broken up by police firing tear gas and live ammunition into the air.
The U.N. peacekeeping mission was heavily criticized last year for standing by when the M23 rebels swept into Goma, the capital of North Kivu province, having routed government forces. The rebels withdrew in return for peace talks, which have repeatedly stalled.
In fresh fighting that began Sunday, the Congolese army pushed the rebels back and, according to the government, inflicted heavy casualties. The area around Goma fell quiet Thursday after four days of heavy fighting.
Civil society representative Nestor Bauma said he believed Ban had a right to express concern about rights abuses. "But he should not forget the realities on the ground. If people think the U.N. is trying to block an army advance you can imagine what can happen," he said.
A Congolese army officer, who insisted on anonymity because he was not authorized to speak to the press, said the army condemned the desecration of corpses but said the perpetrators' "combat stress" should be taken into account.