Libya sends army to stop clashes in southeast TRIPOLI (Reuters) - Libya has sent military forces to stem clashes between rival tribes over control of territory in the far southeast of Libya, the armed forces chief said on Saturday, as more people were reported killed in the violence. Clashes broke out late last week in the remote city of Al Kufra and have continued since, highlighting the challenge of policing the sparsely populated desert. Dozens of people have been killed, the tribes have said. Libya's ruling National Transitional Council has struggled to assert its authority across the whole of Libya as rival regional militias and tribal groups jostle for power and resources following the fall of Muammar Gaddafi. Gunmen from the Zwai tribe have been clashing with fighters from the Tibu ethnic group led by Isa Abdel Majid, who they accuse of attacking Al Kufra backed by mercenaries from Chad, according to a security official from the Zwai tribe. The Tibu, however, said they were the ones to come under attack. Speaking by telephone on Libyan state television, armed forces chief Yousef al-Mangoush denied there was any foreign presence in the area and urged elders from both sides to meet. This is a problem between two tribes, which stems from the past. It is not an ethnic problem," he said. Military forces are now on the ground there. In a text message to Reuters, Adelbari Idriss, a security official from the Zwai tribe, said two people were killed and seven injured in clashes in the city on Saturday. Separately, he said the Zwai had stopped two cars carrying Chadian men. It was not immediately possible to independently verify his comments nor contact officials from the Tibu side. The Tibu are mainly found in Chad but also inhabit parts of southern Libya, Sudan and Niger, often criss-crossing unmarked desert borders. Abdel Majid's men supported the Libyan rebels during the 2011 uprising that ousted Gaddafi. In Al Kufra, tribal ties are far more powerful than they are on the country's Mediterranean seaboard. A tribal rebellion in 2009 was suppressed only after Gaddafi sent in helicopter gunships. The remote region is also a hub for smugglers taking advantage of the lawless borders of sub-Saharan Africa. The province surrounding Al Kufra is Libya's largest and borders Sudan and Chad. The roads in the region are poor, and some reports said the airport was out of use due to the fighting, possibly holding up any aid. Reporting by Ali Shuaib