In 2003, the UN decided to seriously deal with the war in the Congo. It had been going on for six years and the situation in northeastern Congo in 2003 was described as a slow-going genocide. Although a peace agreement had been signed in 2002, it was broken by militia groups in the eastern part of the country. Isberg arrived in Kinshasa, the capital of the Democratic Republic of the Congo (DRC) in late July 2003 to take up his post as deputy force commander of the UN peacekeeping mission in the DRC, known as MONUC. On 21 August 2003, Isberg was appointed acting commander of the Ituri Brigade - the UN force that took over on 1 September from the French-led Interim Emergency Multinational Force (IEMF) that had completed its mandate of securing the eastern town in Bunia in the embattled Ituri District. Overall, Isberg commanded 5,000 men in the Ituri District. The Ituri Brigade included personnel from Morocco, Bangladesh, Nepal and Pakistan; an Indian aviation unit; and a Bangladeshi and Indonesian engineering unit. In October 2003, Isberg, superseded as brigade commander by a Pakistani brigadier general, returned to his regular position at the MONUC headquarters in Kinshasa, a time as Acting Force Commander; the regular, Mountaga Diallo, was replaced in December by major general Somaila Ilyia from Nigeria, a superior with whom Isberg had easy cooperation. Isberg was later appointed commander of the Kivu Brigade from March 2004. He was the only western soldier in his brigade, which was composed of a Uruguayan and a Bangladeshi battalion, totalling 4,000 men.