Human rights groups in the Democratic Republic of Congo have lodged a formal complaint with the government against a senior army officer. <br/><br/>The groups accuse troops under the command of Colonel Innocent Zimurinda of mass killing and rape of civilians. The call for his suspension comes as a U.N-backed Congolese offensive against rebels is due to begin. <br/><br/>Last year, a similar operation caused great controversy as the U.N was accused of condoning human rights abuses. <br/><br/>The 50 human rights groups and civil society organisations, including Human Rights Watch, have written to the commander of the government forces in the North Kivu region.<br/><br/>The organisations said Colonel Zimurinda had been in charge of a group of rebels who killed at least 150 civilians in Kiwanja in late 2008. <br/><br/>According to the human rights groups and a U.N investigation, Colonel Zimurinda was responsible for another massacre in Shalio last April where more than 120 Rwandan Hutu refugees were killed. <br/>