Sudanese government troops have launched attacks on two towns in Darfur, three rebel groups in the region have said. The rebels said the troops, backed by militias, helicopters and planes, had attacked Disa and Birmaza in North Darfur state early on Saturday. The joint United Nations-African Union peacekeeping force in Darfur said it was investigating the reports. There has been no comment on the rebel claims from the Sudanese military. 'String of attacks' "There are many dead, both civilians and some of our soldiers too," a commander of a faction of the rebel Sudan Liberation Army, Ibrahim al-Helwu, was quoted as saying by the AFP news agency. "The fighting is still going on, they are inside the town and are looting," he said from Disa. Commanders of two other rebel groups also said their forces in the area, north of the town of Kutum, were also involved in the fighting. Rebel groups have accused government forces of launching a string of attacks on insurgent-held areas in North Darfur in recent months. One rebel commander, Sherif Harir, from the Sudan Liberation Movement - Unity faction, said Khartoum was trying to wrest control of key transport routes and oil reserves in the area, Reuters news agency reported. The five-year conflict in Darfur has led to the deaths of more than 300,000 people and the displacement of two million others, according to UN estimates. The violence began in 2003 when rebel groups complaining of discrimination against black Africans began attacking government targets. Source: BBC