In the Democratic Republic of Congo, tens of thousands of people took to the streets Sunday in one of the largest mass protests since fighting escalated between the government and the M23 rebel group in recent months. Last week DRC’s armed forces accused M23 of killing at least 50 civilians in the eastern town of Kishishe, violating a five-day ceasefire. M23 denied that it had targeted civilians. The U.N.’s peacekeeping mission in the DRC also denounced the killings and called for an investigation to “bring the perpetrators to justice.” Nearly 400,000 people have been displaced by the fighting.