Goma - Clashes erupted on Sunday between army troops and rebels accused of being behind the disappearance of 20 civilians in the Democratic Republic of Congo's restive east, military and civilian sources told AFP.The fighting occurred in the territory of Beni, the North-Kivu province near the border with Uganda, which has suffered a wave of violence since 2014 with more than 700 civilians killed, many of them hacked to death. The killings have been blamed on a shadowy rebel group, the Allied Democratic Forces (ADF), which is dominated by hardline Ugandan Muslims.The clashes between the ADF and army troops on Sunday took place 40km from the Mbau-Kamango road."The fighting is intense, with heavy and light weapons. The enemy has cut large trees to block the road. We have not yet cleared the road," said army spokesperson Mak Hazukay, who did not give a death toll.On Saturday, the ADF attacked around 10 motorbike taxis on the Mbau-Kamango road, according to Beni administrator Amisi Kalonda."About 20 people are missing. We do not know if they have died or been detained by the ADF," Kalonda said.Teddy Kataliko, a member of a local alliance of NGOs and unions working in Beni, said 22 people were missing and 10 survived the attack.For more than 20 years, eastern DR Congo has been rocked by conflict waged by both domestic and foreign armed groups which has been fuelled by the struggle for control of lucrative mineral resources but also by ethnic and property disputes.