A Chadian armed group attacked a military camp of forces loyal to General Khalifa Haftar in southern Libya on Thursday, killing one fighter, a local official and a spokesman for Haftar said.
After the toppling of Libyan dictator Muammar Gadhafi in a NATO-backed uprising in 2011, fighters from neighboring Chad and Sudan joined the ensuing turmoil. Competing Libyan armed factions frequently accuse each other of deploying mercenaries from sub-Saharan Africa.
Thirteen people were also wounded in the attack, which took place near Traghen, some 900 kilometers (560 miles) south of Tripoli and about 400 kilometers north of the border with Chad, a spokesman for the Traghen municipality said.
Haftar's Libya National Army (LNA) is the military wing of the government that operates in the east of the country. An LNA spokesman, Ahmed Mesmari, said the dead man was one of its members.
The rival, U.N.-backed government of national accord (GNA), which is based in Tripoli, condemned the assault as a violation of Libya's sovereignty.
It also called for all military forces in the country to unify. "Let the Libyan south be the start for countering terrorists and mercenaries together, until we rid the country of them," the GNA said in a statement.
Libya's east-west division, in place since disputed elections and an escalation of fighting in 2014, has split key institutions and produced a deadlock between the rump parliaments and the shifting military factions they are aligned with.