Forces led by military commander Khalifa Haftar announced Thursday that they have fully taken control of Derna city, the final militant stronghold outside of their control in eastern Libya. In a speech on Libyan television, Haftar thanked the people for their support of a military offensive launched on May 7 by his Libyan National Army to seize the city from a rival militia known as the Derna Protection Force.

Seizing Derna completes the takeover of Libya's east by Haftar, who built up the Libyan National Army (LNA) during three-year campaign for Benghazi, Libya's second city. But the Derna fighting could also undercut U.N.-led efforts to stabilise Libya by reconciling eastern-based factions aligned with Haftar and rival groups located in the country's more populous west.

In Derna, the United Nations has warned of the devastating impact of the LNA encirclement and recent fighting on residents. It also expressed alarm earlier this month at allegations of serious human rights abuses including pillage, destruction of property, arbitrary detention and a video of summary executions.

After Haftar declared victory in Benghazi in July last year, fighting continued for several months in parts of the city. In Derna, the LNA's progress has been much faster, aided by what their opponents said were precision air strikes carried out by drones. Neighboring Egypt, one of several foreign powers that has provided support for Haftar, has in the past carried out air strikes in Derna against what it described as training camps sending militants into Egypt to carry out attacks.