Commander of the Libyan National Army Field Marshal Khalifa Haftar announced on Monday the launch of military operations to liberate the eastern city of Derna from terrorists “after peace efforts there reached a dead end.” "The zero hour has struck for the liberation of Derna," said Haftar, declaring his troops had already started to crush the "bastions of terrorists" in the city. “We have given instructions to avoid civilians,” he added during a speech at a military parade in Benghazi. Derna is the last major bastion of opposition to the LNA in eastern Libya. The LNA has surrounded the city, on the coastal highway between Benghazi and Egypt, and has long threatened to begin ground operations there. However, its campaign has so far been limited to encirclement along with occasional air strikes and bombardments. Derna is controlled by a coalition of extremists and rebel veterans known as the Derna Mujahideen Shura Council (DMSC). Egypt, which backs the LNA, has also carried out air strikes in Derna on what it said were training camps sending militants into Egypt. Late on Sunday there were air strikes southeast of Derna, followed by clashes on Monday morning around a flour factory east of Derna. In recent weeks the LNA has deployed new units in the Derna area and at the end of last month Haftar made a rare visit to forces stationed outside the city, following his return from medical treatment in France. The United Nations is leading efforts to stabilize Libya and prepare it for elections before the end of the year. These efforts were met last week with an ISIS-claimed bombing of the electoral commission in the capital Tripoli. Another flashpoint is the southern city of Sabha, where fighting between communal groups that is linked to the wider conflict has escalated in recent weeks. On Sunday, three children in Sabha were killed and five people including their parents were wounded by shelling, the manager of Sabha Medical Center said. Before that, at least 18 people had been killed and 86 wounded in fighting since February, he said.