The Libyan National Army (LNA) of eastern-based commander Khalifa Haftar clashed with Chadian rebel forces in the south of Libya on Tuesday and Wednesday, both sides said.
The fighting underscores the risk of further instability in the Sahel region, where an array of groups operate across borders and where fighting has created space for militant organisations.
Statements from the LNA, which holds most of eastern and southern Libya, said it was engaged in military operations against what it called terrorist groups and the Chadian opposition.
The rebel group Front for Change and Concord in Chad (FACT) said via social media that its positions on the frontier had been attacked by Haftar’s forces, fighting alongside what it said were Sudanese mercenaries and French troops.